Phosphatidylinositol 3-kinase-related kinase

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Phosphatidylinositol 3-kinase-related kinases (PIKKs) are a family of Ser/Thr-protein kinases with sequence similarity to phosphatidylinositol-3 kinases (PI3Ks). [1]

Contents

Members

The human PIKK family includes six members:

GeneProteinFunction
ATM ataxia-telangiectasia mutatedresponse to DNA damage
ATR ataxia- and Rad3-related"
PRKDC DNA-dependent protein kinase catalytic subunit (DNA-PKcs)"
MTOR mammalian target of rapamycin (mTOR)nutrient-regulated kinase that controls metabolism and cell growth
SMG1 suppressor of morphogenesis in genitaliaregulates nonsense-mediated mRNA decay
TRRAP transformation/transcription domain-associated proteintranscription factor co-activator

Structure

PIKKs proteins contain the following four domains:

  1. N-terminus FRAP-ATM- TRRAP (FAT) domain, Pfam PF02259
  2. kinase domain (KD; PI3_PI4_kinase),
  3. PIKK- regulatory domain (PRD), and
  4. C-terminus FAT-C-terminal (FATC) domain Pfam PF02260

Related Research Articles

ATM serine/threonine kinase

ATM serine/threonine kinase, symbol ATM, is a serine/threonine protein kinase that is recruited and activated by DNA double-strand breaks. It phosphorylates several key proteins that initiate activation of the DNA damage checkpoint, leading to cell cycle arrest, DNA repair or apoptosis. Several of these targets, including p53, CHK2, BRCA1, NBS1 and H2AX are tumor suppressors.

Phosphatidylinositol (3,4,5)-trisphosphate

Phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P3), abbreviated PIP3, is the product of the class I phosphoinositide 3-kinases (PI 3-kinases) phosphorylation of phosphatidylinositol (4,5)-bisphosphate (PIP2). It is a phospholipid that resides on the plasma membrane.

Phosphoinositide 3-kinase

Phosphoinositide 3-kinases (PI3Ks), also called phosphatidylinositol 3-kinases, are a family of enzymes involved in cellular functions such as cell growth, proliferation, differentiation, motility, survival and intracellular trafficking, which in turn are involved in cancer.

Class III PI 3-kinase is a subgroup of the enzyme family, phosphoinositide 3-kinase that share a common protein domain structure, substrate specificity and method of activation.

Phosphatidylinositol 4,5-bisphosphate

Phosphatidylinositol 4,5-bisphosphate or PtdIns(4,5)P2, also known simply as PIP2 or PI(4,5)P2, is a minor phospholipid component of cell membranes. PtdIns(4,5)P2 is enriched at the plasma membrane where it is a substrate for a number of important signaling proteins.

Phosphatidylinositol 3-phosphate

Phosphatidylinositol 3-phosphate (PtdIns3P) is a phospholipid found in cell membranes that helps to recruit a range of proteins, many of which are involved in protein trafficking, to the membranes. It is the product of both the class II and III phosphoinositide 3-kinases activity on phosphatidylinositol.

P110δ

Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit delta isoform also known as phosphoinositide 3-kinase (PI3K) delta isoform or p110δ is an enzyme that in humans is encoded by the PIK3CD gene.

GAB2

GRB2-associated-binding protein 2 also known as GAB2 is a protein that in humans is encoded by the GAB2 gene.

Phosphatidylinositol transfer protein

Phosphatidylinositol transfer protein (PITP) or priming in exocytosis protein 3 (PEP3) is a ubiquitous cytosolic domain involved in transport of phospholipids from their site of synthesis in the endoplasmic reticulum and Golgi to other cell membranes.

INPP5D

Src homology 2 (SH2) domain containing inositol polyphosphate 5-phosphatase 1(SHIP1) is an enzyme with phosphatase activity. SHIP1 is structured by multiple domain and is encoded by the INPP5D gene in humans. SHIP1 is expressed predominantly by hematopoietic cells but also, for example, by osteoblasts and endothelial cells. This phosphatase is important for the regulation of cellular activation. Not only catalytic but also adaptor activities of this protein are involved in this process. Its movement from the cytosol to the cytoplasmic membrane, where predominantly performs its function, is mediated by tyrosine phosphorylation of the intracellular chains of cell surface receptors that SHIP1 binds. Insufficient regulation of SHIP1 leads to different pathologies.

PIK3C2B

Phosphatidylinositol-4-phosphate 3-kinase C2 domain-containing beta polypeptide is an enzyme that in humans is encoded by the PIK3C2B gene.

PI4KB

Phosphatidylinositol 4-kinase beta is an enzyme that in humans is encoded by the PI4KB gene.

PI4KA

Phosphatidylinositol 4-kinase alpha is an enzyme that in humans is encoded by the PI4KA gene.

CENTG1

Arf-GAP with GTPase, ANK repeat and PH domain-containing protein 2 is a protein that in humans is encoded by the AGAP2 gene.

PIK3C2G

Phosphatidylinositol-4-phosphate 3-kinase C2 domain-containing gamma polypeptide is an enzyme that in humans is encoded by the PIK3C2G gene.

PI4K2A

Phosphatidylinositol 4-kinase 2-alpha is an enzyme that in humans is encoded by the PI4K2A gene.

Phosphoinositide-dependent kinase-1

In the field of biochemistry, PDPK1 refers to the protein 3-phosphoinositide-dependent protein kinase-1, an enzyme which is encoded by the PDPK1 gene in humans. It is implicated in the development and progression of melanomas.

Sorting nexin

Sorting nexins are a large group of proteins that are localized in the cytoplasm and have the potential for membrane association either through their lipid-binding PX domain or through protein–protein interactions with membrane-associated protein complexes Some members of this family have been shown to facilitate protein sorting.

mTOR inhibitors

mTOR inhibitors are a class of drugs that inhibit the mammalian target of rapamycin (mTOR), which is a serine/threonine-specific protein kinase that belongs to the family of phosphatidylinositol-3 kinase (PI3K) related kinases (PIKKs). mTOR regulates cellular metabolism, growth, and proliferation by forming and signaling through two protein complexes, mTORC1 and mTORC2. The most established mTOR inhibitors are so-called rapalogs, which have shown tumor responses in clinical trials against various tumor types.

Leonard (Len) R Stephens FRS is a molecular biologist, senior group leader and associate director at the Babraham Institute.

References

  1. Lempiäinen H, Halazonetis TD (October 2009). "Emerging common themes in regulation of PIKKs and PI3Ks". EMBO J. 28 (20): 3067–73. doi:10.1038/emboj.2009.281. PMC   2752028 . PMID   19779456.