PTPRK

PTPRK
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 2C7S
Identifiers
Aliases	PTPRK , R-PTP-kappa, protein tyrosine phosphatase, receptor type K, protein tyrosine phosphatase receptor type K
External IDs	OMIM: 602545; MGI: 103310; HomoloGene: 55693; GeneCards: PTPRK; OMA:PTPRK - orthologs
Gene location (Human) Chr. Chromosome 6 (human) [1] Band 6q22.33 Start 127,968,785 bp [1] End 128,520,616 bp [1]
Gene location (Mouse) Chr. Chromosome 10 (mouse) [2] Band 10 A4|10 15.06 cM Start 27,950,816 bp [2] End 28,473,393 bp [2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in corpus callosum epithelium of colon gallbladder duodenum Achilles tendon superior frontal gyrus islet of Langerhans rectum stromal cell of endometrium stomach Top expressed in tail of embryo genital tubercle barrel cortex Paneth cell ciliary body right kidney iris Region I of hippocampus proper epithelium of lens vestibular membrane of cochlear duct More reference expression data BioGPS More reference expression data
Gene ontology Molecular function beta-catenin binding phosphoprotein phosphatase activity gamma-catenin binding phosphatase activity protein binding protein tyrosine phosphatase activity transmembrane receptor protein tyrosine phosphatase activity protein kinase binding hydrolase activity Cellular component integral component of membrane membrane cell-cell junction adherens junction photoreceptor outer segment integral component of plasma membrane cell surface axon neuronal cell body dendrite leading edge membrane plasma membrane cell junction intracellular membrane-bounded organelle Biological process negative regulation of keratinocyte proliferation cellular response to UV protein dephosphorylation negative regulation of cell cycle cellular response to reactive oxygen species focal adhesion assembly cell adhesion negative regulation of cell migration protein localization to cell surface negative regulation of transcription, DNA-templated neuron projection development transforming growth factor beta receptor signaling pathway cell migration signal transduction negative regulation of cell population proliferation dephosphorylation peptidyl-tyrosine dephosphorylation Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 5796 19272 Ensembl ENSG00000152894 ENSG00000273993 ENSMUSG00000019889 UniProt Q15262 P35822 RefSeq (mRNA) NM_001135648 NM_001291981 NM_001291982 NM_001291983 NM_001291984 NM_002844 NM_008983 NM_001359355 NM_001359356 RefSeq (protein) NP_001129120 NP_001278910 NP_001278911 NP_001278912 NP_001278913 NP_002835 NP_033009 NP_001346284 NP_001346285 Location (UCSC) Chr 6: 127.97 – 128.52 Mb Chr 10: 27.95 – 28.47 Mb PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

Receptor-type tyrosine-protein phosphatase kappa is an enzyme that in humans is encoded by the PTPRK gene. ^{[5] [6] [7]} PTPRK is also known as PTPkappa and PTPκ.

Function

The protein encoded by this gene is a member of the protein tyrosine phosphatase (PTP) family. Protein tyrosine phosphatases are protein enzymes that remove phosphate moieties from tyrosine residues on other proteins. Tyrosine kinases are enzymes that add phosphates to tyrosine residues, and are the opposing enzymes to PTPs. PTPs are known to be signaling molecules that regulate a variety of cellular processes including cell growth, differentiation, mitotic cycle, and oncogenic transformation.

The human PTPRK gene is located on the long arm of chromosome 6, a putative tumor suppressor region of the genome. ^[8]

During development

The same reporter construct used by Shen and colleagues, and described above was created by Skarnes et al. during a screen to identify genes important in mouse development. ^[9] The transgenic mouse was created by combining a β-galactosidase (β-gal) reporter gene with a signal sequence and the transmembrane domain of the type I transmembrane protein CD4. If the transgene was incorporated into a gene with a signal sequence, β-gal activity would remain in the cytosol of the cell and therefore be active. If the reporter gene was incorporated into a gene that lacked a signal sequence, β-gal activity would be in the ER where it would lose β-gal activity. This construct inserted into the phosphatase domain of PTPkappa. ^[10] Mice generated from these ES cells were viable, suggesting that PTPkappa phosphatase activity is not necessary for embryonic development. ^{[9] [10]}

Additional studies have suggested a function for PTPkappa during nervous system development. PTPkappa promotes neurite outgrowth from embryonic cerebellar neurons, and thus may be involved in axonal extension or guidance in vivo. ^[11] Neurites are extensions from neurons that can be considered the in vitro equivalent of axons and dendrites. The extension of cerebellar neurites on purified PTPkappa fusion proteins was demonstrated to require Grb2 and MEK1 activity. ^[11]

In T cells

PTPkappa has also been shown to regulate CD4+ positive T cell development. ^[12] PTPkappa and the THEMIS gene are both deleted in the rat Long-Evans Cinnamon (LEC) strain, and are both required for the CD4+ T-cell deficiency observed in this strain of rats. ^{[12] [13]} Deletion of PTPkappa was shown to generate T-helper immunodeficiency in the LEC strain. ^[14]

By expressing a dominant negative form of PTPkappa or by using short-hairpin RNA for PTPkappa in bone-marrow derived stem cells, CD4(+) T cells development is inhibited. ^[15] PTPkappa likely regulates T-cell development by positively regulating ERK1/2 phosphorylation via the regulation of MEK1/2 and c-Raf phosphorylation. ^[15]

Cadherin-catenin signaling

PTPkappa is localized to cell-cell contact sites, where it colocalizes and co-immunoprecipitates with β-catenin and plakoglobin/γ-catenin ^[6] β-catenin may be a PTPkappa substrate. ^{[6] [16]} The presence of full-length PTPkappa in melanoma cells decreases the level of free-cytosolic β-catenin, which consequently reduces the level of nuclear β-catenin and reduces the expression of the β-catenin-regulated genes, cyclin D1 and c-myc. ^[17] Expression of ful-length PTPkappa in melanoma cells that normally lack its expression results in reduced cell migration and cell proliferation. Because the presence of PTPkappa at the cell membrane was shown to sequester β-catenin to the plasma membrane, these data suggest that one mechanism whereby PTPkappa functions as a tumor suppressor is by regulating the intracellular localization of free-β-catenin. ^[17]

The intracellular fragments of PTPkappa, PΔE and PIC, are catalytically active, and can also dephosphorylate β-catenin. ^[16] Tyrosine phosphorylated β-catenin translocates to the cell nucleus and activates TCF-mediated transcription to promote cell proliferation and migration. While full-length PTPkappa antagonizes TCF-mediated transcription, the PIC fragment augments it, perhaps by regulating other proteins in TCF-mediated transcription. ^[16] This suggests that phosphatase activity of the PIC fragment opposes that of full-length PTPkappa. ^[16]

PTPkappa interacts by co-immunoprecipitation with E-cadherin, α-catenin and β-catenin in pancreatic acinar cells prior to the dissolution of adherens junctions in a rat model of pancreatitis. ^[18] The authors suggest that the presence of PTPkappa at the plasma membrane in association with the cadherin/catenin complex is important for the maintenance of adherens junction in pancreatic acinar cells, much as it was suggested above in melanoma cells. ^[18]

EGFR signaling

Use of short interfering RNA (siRNA) of PTPkappa to reduce PTPkappa protein expression in the mammary epithelial cell line, MCF10A, resulted in increased cell proliferation. ^[19] PTPkappa expression, conversely, was demonstrated to reduce cell proliferation in Chinese hamster ovary cells. ^[20] The mechanism proposed to explain the influence of PTPkappa on cell proliferation is via PTPkappa dephosphorylation of the EGFR on tyrosines 1068 and 1173 directly. The reduction of PTPkappa expression in CHO cells with PTPkappa siRNA increased EGFR phosphorylation. ^[20] Therefore, the hypothesis is that PTPkappa functions as a tumor suppressor gene by dephosphorylating and inactivating EGFR. ^[20]

In addition, glycosylation by N-acetylglucosaminyltransferase-V (GnT-V) has been shown to reduce full-length PTPkappa expression, likely via increasing its cleavage. ^[21] This aberrant glycosylation has been shown to increase the phosphorylation of EGFR on tyrosine 1068, likely because of reduced plasma-membrane associated PTPkappa expression and hence reduced PTPkappa-mediated dephosphorylation of its membrane associated substrates, such as EGFR. ^[22]

Structure

PTPkappa possesses an extracellular region, a single transmembrane region, and two tandem catalytic domains, and thus represents a receptor-type PTP (RPTP). The extracellular region contains a meprin-A5 antigen-PTP mu (MAM) domain, an Ig-like domain and four fibronectin type III-like repeats. ^[23] PTPkappa is a member of the R2B subfamily of RPTPs, which includes RPTPM, RPTPT, and RPTPU. PTPkappa shares most sequence similarity with PTPmu and PTPrho.

Crystal structure analysis of the first phosphatase domain of PTPkappa demonstrates that it shares many conformational features with PTPmu, including an unhindered open conformation for the catalytically important WPD loop, and a phosphate binding loop for the active-site cysteine (Cys1083). PTPkappa exists as a monomer in solution, with the caveat that dimers of PTPkappa are observed depending on the nature of the buffer used. ^[24]

Alternative splicing

Alternative splicing of exons 16, 17a, and 20a has been described for PTPRK. ^[25] Two novel forms of PTPRK were identified from mouse full-length cDNA sequences and were predicted to result in two PTPkappa splice variants: a secreted form of PTPkappa and a membrane tethered form. ^[26]

Homophilic binding

PTPkappa mediates homophilic cell-cell aggregation via its extracellular domain. ^[27] PTPkappa only mediates binding between cells expressing PTPkappa (i.e. homophilic), and will not mediate cell aggregation between cells expressing PTPkappa, PTPmu or PTPrho (i.e. heterophilic). ^{[28] [29]}

Regulation

Proteolysis and N-glycosylation

Full-length PTPkappa protein is cleaved by furin to generate two cleaved fragments that remain associated at the plasma membrane, an extracellular (E) subunit and an intracellular phosphatase (P) subunit. ^{[6] [23]} In response to high cell density or calcium influx following trifluoperazine (TFP) stimulation, PTPkappa is further cleaved by ADAM 10 to yield a shed extracellular fragment and a membrane tethered intracellular fragment, PΔE. ^[16] The membrane tethered PΔE fragment is further cleaved by the gamma secretase complex to yield a membrane-released fragment, PIC, that can translocate to the cellular nucleus, where it is catalytically active. ^[16]

Glycosylation of the extracellular domain of PTPkappa was demonstrated to occur preferentially in WiDr colon cancer cells that over-express N-acetylglucosaminyl transferase V (GnT-V). ^[21] Over-expression of GnT-V in these cells increased the cleavage and shedding of PTPkappa ectodomain and increased migration of WiDr cells in transwell assays. ^[21] As a result of glycosylation of PTPkappa by GnT-V, EGFR was phosphorylated on tyrosine 1068 and activated, and is likely the cause of the increased cell migration observed following PTPkappa cleavage. ^[22]

Shedding of PTPkappa may also be regulated by the presence of galectin-3 binding protein, as has been shown in WiDr cells. ^[30] The authors suggest that the ratio of galectin-3 binding protein to galectin 3 influences the cleavage and shedding of PTPkappa, although the exact mechanism of how these proteins regulate PTPkappa cleavage was not determined.

By reactive oxygen species in cancer

One mechanism whereby PTPkappa tyrosine phosphatase activity can be perturbed in cancer is via oxidative inhibition mediated by reactive oxygen species generated by either hydrogen peroxide in vitro or UV irradiation of skin cells in vivo. ^[31] In cell-free assays, the presence of hydrogen peroxide reduces PTPkappa tyrosine phosphatase activity and increases EGFR tyrosine phosphorylation. ^[31] UV-irradiation of primary human keratinocytes yields the same results, namely a reduction of PTPkappa tyrosine phosphatase activity and an increase in EGFR tyrosine phosphorylation. EGFR phosphorylation then leads to cell proliferation, suggesting that PTPkappa may function as a tumor suppressor in skin cancer in addition to melanoma. ^[31]

Expression

PTPkappa is expressed in human keratinocytes. TGFβ1 is a growth inhibitor in human keratinocytes. Stimulation of the cultured human keratinocyte cell line, HaCaT, with TGFβ1 increases the levels of PTPkappa (PTPRK) mRNA as assayed by northern blot analysis. ^[32] TGFβ1 also increased PTPkappa mRNA and protein in normal and tumor mammary cell lines. ^[19] HER2 overexpression reduced PTPkappa mRNA and protein expression. ^[19]

Clinical significance

Melanoma and skin cancer

Expression analysis of PTPkappa mRNA in normal melanocytes and in melanoma cells and tissues demonstrated that PTPkappa is downregulated or absent 20% of the time in melanoma, suggesting that PTPkappa is a tumor suppressor gene in melanoma. ^[33] A form of PTPkappa with a point mutation in the fourth fibronectin III repeat was identified to be a melanoma specific antigen recognized by CD4+ T cells in a melanoma patient with 10-year tumor-free survival after lymph node resection. ^[34] This particular mutated form of PTPkappa was not identified in 10 other melanoma cell lines, and may thus represent a unique mutation in one patient. ^[34]

Lymphoma

PTPkappa was also identified as the putative tumor suppressor gene commonly deleted in primary central nervous system lymphomas (PCNSLs). ^[35]

Downregulation of PTPkappa was found to occur following Epstein-Barr Virus (EBV) infection of Hodgkin's Lymphomas cells. ^[36]

Colorectal cancer

Using a transposon-based genetic screen, researchers found that disruption of the PTPRK gene in gastrointestinal tract epithelium resulted in an intestinal lesion, classified as either an intraepithelial neoplasia, an adenocarcinoma or an adenoma. ^[37]

Lung cancer

PTPRK mRNA was shown to be significantly reduced by RT-PCR in human lung cancer-derived cell lines. ^[38]

Prostate cancer

PTPRK has also been shown to be downregulated in response to androgen stimulation in human LNCaP prostate cancer cells. ^[39] The mechanism whereby PTPRK is downregulated is via the expression of a microRNA, miR-133b, which is upregulated in response to androgen stimulation. ^[39]

Breast cancer

Patients with reduced PTPRK transcript expression have shorter breast cancer survival times and are more likely to have breast cancer metastases or to die from breast cancer. ^[40] In an experimental model of breast cancer, PTPRK was reduced in breast cancer cell lines with PTPRK ribozymes. ^[40] In these cells, adhesion to matrigel, transwell migration, and cell growth were all increased following the reduction of PTPRK expression, again supporting a function for PTPRK as a tumor suppressor. ^[40]

Glioma

Assem and colleagues identified loss of heterozygosity (LOH) events in malignant glioma specimens, and identified PTPRK as a significant gene candidate in one LOH region. ^[41] A significant correlation between the presence of PTPRK mutations and short patient survival time was observed. ^[41] PTPRK was amplified from tumor cDNA to confirm the LOH observed. In these specimens, 6 different mutations were observed, two of which (one in each phosphatase domain) disrupted the enzymatic activity of PTPRK. ^[42] Expression of wild-type PTPkappa in U87-MG and U251-MG cells resulted in a reduction in cell proliferation, migration and invasion. ^[42] Expression of the variants of PTPkappa with mutations in the phosphatase domains, however, increased cell proliferation, migration and invasion, supporting a role for the involvement of the mutated variants of PTPkappa in tumorigenicity. ^[42]

In development

In situ hybridization localized PTPkappa mRNA to the brain, lung, skeletal muscle, heart, placenta, liver, kidney and intestines during development. ^[43] PTPkappa was also found to be expressed in the developing retina, in nestin-positive radial progenitor cells and later in development, in the ganglion cell layer, inner plexiform layer and outer segments of photoreceptors. ^[44] PTPkappa protein is observed in neural progenitor cells and radial glial cells of the developing mouse superior colliculus, as well. ^[45]

In the adult rat brain, PTPkappa mRNA is highly expressed in regions of the brain with cellular plasticity and growth, such as the olfactory bulb, the hippocampus and the cerebral cortex. ^[23] PTPkappa mRNA is also observed in the adult mouse cerebellum. ^[25]

Using a β-galactosidase (β-gal) reporter gene inserted into the phosphatase domain of the murine PTPkappa (PTPRK) gene, Shen and colleagues determined the detailed expression pattern of endogenous PTPRK. ^[10] β-gal activity was observed in many areas of the adult forebrain, including layers II and IV, and to a lesser extent in layer VI of the cortex. β-gal activity was also observed in apical dendrites of cortical pyramidal cells, the granule layer of the olfactory and accessory olfactory bulbs, the anterior hypothalamus, paraventricular nucleus, and in granule and pyramidal layers of the dentate gyrus and CA 1-3 regions of the hippocampus. ^[10] In the midbrain, β-gal was observed in the subthalamic nucleus, the superior and inferior colliculi and in the red nucleus. β-gal activity was also observed in the neural retina, in the inner nuclear layer and in small ganglion cells of the ganglion cell layer. ^[10]

Interactions

PTPRK has been shown to interact with:

• Beta-catenin, ^{[6] [16] [18]}
• E-cadherin (CDH-1), ^[18]
• Epidermal growth factor receptor (EGFR), ^[19]
• HER2, ^[19]
• Plakoglobin, ^[6] and
• α-catenin. ^[18]

References

1. ENSG00000273993 GRCh38: Ensembl release 89: ENSG00000152894, ENSG00000273993 – Ensembl, May 2017
2. GRCm38: Ensembl release 89: ENSMUSG00000019889 – Ensembl, May 2017
3. "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
4. "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
5. Yang Y, Gil MC, Choi EY, Park SH, Pyun KH, Ha H (Mar 1997). "Molecular cloning and chromosomal localization of a human gene homologous to the murine R-PTP-kappa, a receptor-type protein tyrosine phosphatase". Gene. 186 (1): 77–82. doi:10.1016/S0378-1119(96)00684-1. PMID   9047348.
6. Fuchs M, Müller T, Lerch MM, Ullrich A (Aug 1996). "Association of human protein-tyrosine phosphatase kappa with members of the armadillo family". J Biol Chem. 271 (28): 16712–9. doi: 10.1074/jbc.271.28.16712 . PMID   8663237.
7. "Entrez Gene: PTPRK protein tyrosine phosphatase, receptor type, K".{{cite web}}: Missing or empty |url= (help)
8. Zhang Y, Siebert R, Matthiesen P, Yang Y, Ha H, Schlegelberger B (1998). "Cytogenetical assignment and physical mapping of the human R-PTP-kappa gene (PTPRK) to the putative tumor suppressor gene region 6q22.2-q22.3". Genomics. 51 (2): 309–11. doi: 10.1006/geno.1998.5323 . PMID   9722959.
9. Skarnes WC, Moss JE, Hurtley SM, Beddington RS (1995). "Capturing genes encoding membrane and secreted proteins important for mouse development". Proc Natl Acad Sci U S A. 92 (14): 6592–6. Bibcode:1995PNAS...92.6592S. doi: 10.1073/pnas.92.14.6592 . PMC   41564 . PMID   7604039.
10. Shen P, Canoll PD, Sap J, Musacchio JM (1999). "Expression of a truncated receptor protein tyrosine phosphatase kappa in the brain of an adult transgenic mouse". Brain Res. 826 (2): 157–71. doi: 10.1016/s0006-8993(99)01179-8 . PMID   10224293. S2CID   40530391.
11. Drosopoulos NE, Walsh FS, Doherty P (1999). "A soluble version of the receptor-like protein tyrosine phosphatase kappa stimulates neurite outgrowth via a Grb2/MEK1-dependent signaling cascade". Mol Cell Neurosci. 13 (6): 441–9. doi:10.1006/mcne.1999.0758. PMID   10383829. S2CID   35458154.
12. Kose H, Sakai T, Tsukumo S, Wei K, Yamada T, Yasutomo K, Matsumoto K (2007). "Maturational arrest of thymocyte development is caused by a deletion in the receptor-like protein tyrosine phosphatase kappa gene in LEC rats". Genomics. 89 (6): 673–7. doi:10.1016/j.ygeno.2007.03.001. PMID   17434290. S2CID   28407283.
13. Iwata R, Sasaki N, Agui T (2010). "Contiguous gene deletion of Ptprk and Themis causes T-helper immunodeficiency (thid) in the LEC rat". Biomed Res. 31 (1): 83–7. doi: 10.2220/biomedres.31.83 . PMID   20203423.
14. Asano A, Tsubomatsu K, Jung CG, Sasaki N, Agui T (2007). "A deletion mutation of the protein tyrosine phosphatase kappa (Ptprk) gene is responsible for the CD4+ T-cell immunodeficiency (thid) in the LEC rat" (PDF). Mamm Genome. 18 (11): 779–86. doi:10.1007/s00335-007-9062-0. hdl: 2115/33866 . PMID   17909891. S2CID   20866657.
15. Erdenebayar N, Maekawa Y, Nishida J, Kitamura A, Yasutomo K (2009). "Protein-tyrosine phosphatase-kappa regulates CD4+ T cell development through ERK1/2-mediated signaling". Biochem Biophys Res Commun. 390 (3): 489–93. doi:10.1016/j.bbrc.2009.09.117. PMID   19800317.
16. Anders L, Mertins P, Lammich S, Murgia M, Hartmann D, Saftig P, Haass C, Ullrich A (2006). "Furin-, ADAM 10-, and gamma-secretase-mediated cleavage of a receptor tyrosine phosphatase and regulation of beta-catenin's transcriptional activity". Mol Cell Biol. 26 (10): 3917–34. doi:10.1128/MCB.26.10.3917-3934.2006. PMC   1489012 . PMID   16648485.
17. Novellino L, De Filippo A, Deho P, Perrone F, Pilotti S, Parmiani G, Castelli C (2008). "PTPRK negatively regulates transcriptional activity of wild type and mutated oncogenic beta-catenin and affects membrane distribution of beta-catenin/E-cadherin complexes in cancer cells". Cell Signal. 20 (5): 872–83. doi:10.1016/j.cellsig.2007.12.024. PMID   18276111.
18. Schnekenburger J, Mayerle J, Krüger B, Buchwalow I, Weiss FU, Albrecht E, Samoilova VE, Domschke W, Lerch MM (2005). "Protein tyrosine phosphatase kappa and SHP-1 are involved in the regulation of cell-cell contacts at adherens junctions in the exocrine pancreas". Gut. 54 (10): 1445–55. doi:10.1136/gut.2004.063164. PMC   1774702 . PMID   15987791.
19. Wang SE, Wu FY, Shin I, Qu S, Arteaga CL (2005). "Transforming growth factor {beta} (TGF-{beta})-Smad target gene protein tyrosine phosphatase receptor type kappa is required for TGF-{beta} function". Mol Cell Biol. 25 (11): 4703–15. doi:10.1128/MCB.25.11.4703-4715.2005. PMC   1140650 . PMID   15899872.
20. Xu Y, Tan LJ, Grachtchouk V, Voorhees JJ, Fisher GJ (2005). "Receptor-type protein-tyrosine phosphatase-kappa regulates epidermal growth factor receptor function". J Biol Chem. 280 (52): 42694–700. doi: 10.1074/jbc.M507722200 . PMID   16263724.
21. Kim YS, Kang HY, Kim JY, Oh S, Kim CH, Ryu CJ, Miyoshi E, Taniguchi N, Ko JH (2006). "Identification of target proteins of N-acetylglucosaminyl transferase V in human colon cancer and implications of protein tyrosine phosphatase kappa in enhanced cancer cell migration". Proteomics. 6 (4): 1187–91. doi:10.1002/pmic.200500400. PMID   16404719. S2CID   6580919.
22. Wang C, Yang Y, Yang Z, Liu M, Li Z, Sun L, Mei C, Chen H, Chen L, Wang L, Zha X (2009). "EGF-mediated migration signaling activated by N-acetylglucosaminyltransferase-V via receptor protein tyrosine phosphatase kappa". Arch Biochem Biophys. 486 (1): 64–72. doi:10.1016/j.abb.2009.02.005. PMID   19236842.
23. Jiang YP, Wang H, D'Eustachio P, Musacchio JM, Schlessinger J, Sap J (1993). "Cloning and characterization of R-PTP-kappa, a new member of the receptor protein tyrosine phosphatase family with a proteolytically cleaved cellular adhesion molecule-like extracellular region". Mol Cell Biol. 13 (5): 2942–51. doi:10.1128/MCB.13.5.2942. PMC   359687 . PMID   8474452.
24. Eswaran J, Debreczeni JE, Longman E, Barr AJ, Knapp S (2006). "The crystal structure of human receptor protein tyrosine phosphatase kappa phosphatase domain 1". Protein Sci. 15 (6): 1500–5. doi:10.1110/ps.062128706. PMC   2242534 . PMID   16672235.
25. Besco J, Popesco MC, Davuluri RV, Frostholm A, Rotter A (2004). "Genomic structure and alternative splicing of murine R2B receptor protein tyrosine phosphatases (PTPkappa, mu, rho and PCP-2)". BMC Genomics. 5 (1): 14. doi: 10.1186/1471-2164-5-14 . PMC   373446 . PMID   15040814.
26. Forrest AR, Taylor DF, Crowe ML, Chalk AM, Waddell NJ, Kolle G, Faulkner GJ, Kodzius R, Katayama S, Wells C, Kai C, Kawai J, Carninci P, Hayashizaki Y, Grimmond SM (2006). "Genome-wide review of transcriptional complexity in mouse protein kinases and phosphatases". Genome Biol. 7 (1): R5. doi: 10.1186/gb-2006-7-1-r5 . PMC   1431701 . PMID   16507138.
27. Sap J, Jiang YP, Friedlander D, Grumet M, Schlessinger J (1994). "Receptor tyrosine phosphatase R-PTP-kappa mediates homophilic binding". Mol Cell Biol. 14 (1): 1–9. doi:10.1128/MCB.14.1.1. PMC   358350 . PMID   8264577.
28. Zondag GC, Koningstein GM, Jiang YP, Sap J, Moolenaar WH, Gebbink MF (1995). "Homophilic interactions mediated by receptor tyrosine phosphatases mu and kappa. A critical role for the novel extracellular MAM domain". J Biol Chem. 270 (24): 14247–50. doi: 10.1074/jbc.270.24.14247 . PMID   7782276.
29. Becka S, Zhang P, Craig SE, Lodowski DT, Wang Z, Brady-Kalnay SM (2010). "Characterization of the adhesive properties of the type IIb subfamily receptor protein tyrosine phosphatases". Cell Commun Adhes. 17 (2): 34–47. doi:10.3109/15419061.2010.487957. PMC   3337334 . PMID   20521994.
30. Kim YS, Jung JA, Kim HJ, Ahn YH, Yoo JS, Oh S, Cho C, Yoo HS, Ko JH (2011). "Galectin-3 binding protein promotes cell motility in colon cancer by stimulating the shedding of protein tyrosine phosphatase kappa by proprotein convertase 5". Biochem Biophys Res Commun. 404 (1): 96–102. doi:10.1016/j.bbrc.2010.11.071. PMID   21094132.
31. Xu Y, Shao Y, Voorhees JJ, Fisher GJ (2006). "Oxidative inhibition of receptor-type protein-tyrosine phosphatase kappa by ultraviolet irradiation activates epidermal growth factor receptor in human keratinocytes". J Biol Chem. 281 (37): 27389–97. doi: 10.1074/jbc.M602355200 . PMC   3738260 . PMID   16849327.
32. Yang Y, Gil M, Byun SM, Choi I, Pyun KH, Ha H (1996). "Transforming growth factor-beta1 inhibits human keratinocyte proliferation by upregulation of a receptor-type tyrosine phosphatase R-PTP-kappa gene expression". Biochem Biophys Res Commun. 228 (3): 807–12. doi:10.1006/bbrc.1996.1736. PMID   8941358.
33. McArdle L, Rafferty M, Maelandsmo GM, Bergin O, Farr CJ, Dervan PA, O'Loughlin S, Herlyn M, Easty DJ (2001). "Protein tyrosine phosphatase genes downregulated in melanoma". J Invest Dermatol. 117 (5): 1255–60. doi: 10.1046/j.0022-202x.2001.01534.x . PMID   11710941.
34. Novellino L, Renkvist N, Rini F, Mazzocchi A, Rivoltini L, Greco A, Deho P, Squarcina P, Robbins PF, Parmiani G, Castelli C (2003). "Identification of a mutated receptor-like protein tyrosine phosphatase kappa as a novel, class II HLA-restricted melanoma antigen". J Immunol. 170 (12): 6363–70. doi: 10.4049/jimmunol.170.12.6363 . PMID   12794170.
35. Nakamura M, Kishi M, Sakaki T, Hashimoto H, Nakase H, Shimada K, Ishida E, Konishi N (2003). "Novel tumor suppressor loci on 6q22-23 in primary central nervous system lymphomas". Cancer Res. 63 (4): 737–41. PMID   12591717.
36. Flavell JR, Baumforth KR, Wood VH, Davies GL, Wei W, Reynolds GM, Morgan S, Boyce A, Kelly GL, Young LS, Murray PG (2008). "Down-regulation of the TGF-beta target gene, PTPRK, by the Epstein-Barr virus encoded EBNA1 contributes to the growth and survival of Hodgkin lymphoma cells". Blood. 111 (1): 292–301. doi: 10.1182/blood-2006-11-059881 . PMID   17720884.
37. Starr TK, Allaei R, Silverstein KA, Staggs RA, Sarver AL, Bergemann TL, Gupta M, O'Sullivan MG, Matise I, Dupuy AJ, Collier LS, Powers S, Oberg AL, Asmann YW, Thibodeau SN, Tessarollo L, Copeland NG, Jenkins NA, Cormier RT, Largaespada DA (2009). "A transposon-based genetic screen in mice identifies genes altered in colorectal cancer". Science. 323 (5922): 1747–50. Bibcode:2009Sci...323.1747S. doi:10.1126/science.1163040. PMC   2743559 . PMID   19251594.
38. Scrima M, De Marco C, De Vita F, Fabiani F, Franco R, Pirozzi G, Rocco G, Malanga D, Viglietto G (2012). "The nonreceptor-type tyrosine phosphatase PTPN13 is a tumor suppressor gene in non-small cell lung cancer". Am J Pathol. 180 (3): 1202–14. doi: 10.1016/j.ajpath.2011.11.038 . PMID   22245727.
39. Mo W, Zhang J, Li X, Meng D, Gao Y, Yang S, Wan X, Zhou C, Guo F, Huang Y, Amente S, Avvedimento EV, Xie Y, Li Y (2013). "Identification of novel AR-targeted microRNAs mediating androgen signalling through critical pathways to regulate cell viability in prostate cancer". PLOS ONE. 8 (2): e56592. Bibcode:2013PLoSO...856592M. doi: 10.1371/journal.pone.0056592 . PMC   3579835 . PMID   23451058.
40. Sun PH, Ye L, Mason MD, Jiang WG (2013). "Protein tyrosine phosphatase kappa (PTPRK) is a negative regulator of adhesion and invasion of breast cancer cells, and associates with poor prognosis of breast cancer". J Cancer Res Clin Oncol. 139 (7): 1129–39. doi:10.1007/s00432-013-1421-5. PMID   23552869. S2CID   20002233.
41. Assem M, Sibenaller Z, Agarwal S, Al-Keilani MS, Alqudah MA, Ryken TC (2012). "Enhancing diagnosis, prognosis, and therapeutic outcome prediction of gliomas using genomics". OMICS. 16 (3): 113–22. doi:10.1089/omi.2011.0031. PMC   3300066 . PMID   22401657.
42. Agarwal S, Al-Keilani MS, Alqudah MA, Sibenaller ZA, Ryken TC, Assem M (2013). "Tumor derived mutations of protein tyrosine phosphatase receptor type k affect its function and alter sensitivity to chemotherapeutics in glioma". PLOS ONE. 8 (5): e62852. Bibcode:2013PLoSO...862852A. doi: 10.1371/journal.pone.0062852 . PMC   3656086 . PMID   23696788.
43. Fuchs M, Wang H, Ciossek T, Chen Z, Ullrich A (1998). "Differential expression of MAM-subfamily protein tyrosine phosphatases during mouse development". Mech Dev. 70 (1–2): 91–109. doi: 10.1016/S0925-4773(97)00179-2 . PMID   9510027. S2CID   9560178.
44. Horvat-Bröcker A, Reinhard J, Illes S, Paech T, Zoidl G, Harroch S, Distler C, Knyazev P, Ullrich A, Faissner A (2008). "Receptor protein tyrosine phosphatases are expressed by cycling retinal progenitor cells and involved in neuronal development of mouse retina". Neuroscience. 152 (3): 618–45. doi:10.1016/j.neuroscience.2008.01.016. PMID   18308476. S2CID   21471047.
45. Reinhard J, Horvat-Bröcker A, Illes S, Zaremba A, Knyazev P, Ullrich A, Faissner A (2009). "Protein tyrosine phosphatases expression during development of mouse superior colliculus". Exp Brain Res. 199 (3–4): 279–97. doi:10.1007/s00221-009-1963-6. PMC   2845883 . PMID   19727691.

Further reading

• Lu J, Li Q, Donadel G, Notkins AL, Lan MS (1998). "Profile and differential expression of protein tyrosine phosphatases in mouse pancreatic islet tumor cell lines". Pancreas. 16 (4): 515–20. doi:10.1097/00006676-199805000-00010. PMID   9598814. S2CID   35807441.
• Bondar C, Plaza-Izurieta L, Fernandez-Jimenez N, Irastorza I, Withoff S, Wijmenga C, Chirdo F, Bilbao JR (2013). "THEMIS and PTPRK in celiac intestinal mucosa: coexpression in disease and after in vitro gliadin challenge". Eur J Hum Genet. 22 (3): 358–62. doi:10.1038/ejhg.2013.136. PMC   3925264 . PMID   23820479.