Coiled-coil domain-containing protein 138, also known as CCDC138, is a human protein encoded by the CCDC138 gene. The exact function of CCDC138 is unknown.
The CCDC138 gene can be found at the positive strand of chromosome 2. [5]
The CCDC138 gene is located at the long(q) arm of chromosome 2 at locus 12.13, [6] or in short 2q12.3. It can be found at location 108,786,752-108,876,591. [7] The DNA sequence is 89,840bp long.
CCDC138 is the only established common alias.
No paralogs of CCDC138 have been identified.
CCDC138 is conserved in various organisms as shown in the table below.
Scientific name | Common name | Date of divergence from human lineage [8] | Sequence length | Sequence identity to human RNA/protein | Sequence similarity to human RNA/protein |
---|---|---|---|---|---|
Mus musculus | House mouse | 92.3 MYA | 2466 bp | 77% | 65.7% |
Columbia livia | Rock dove | 296 MYA | 1863 bp | 61% | 59.4% |
Xenopus laevis | African clawed frog | 371.2 MYA | 2634 bp | 52% | 40.1% |
Anolis carolinensis | Red-throated anole | 296 MYA | 9588 bp | 78% | 46.3% |
Latimeria chalumnae | West Indian Ocean coelacanth | 414.9 MYA | 1838 bp | 71% | 38.1% |
Strongylocentrotus purpuratus | Purple sea urchin | 742.9 MYA | 2047 bp | 59% | 14.5% |
Ciona intestinalis | Vase tunicate | 722.5 MYA | 2420 bp | 56% | 23.8% |
Aplysia californica | California sea slug | 782.7 MYA | 2103 bp | 49% | 17.2% |
Hydra vulgaris | Fresh-water polyp | 855.3 MYA | 1482 bp | 46% | 13.7% |
Chrysemys picta bellii | Western painted turtle | 296 MYA | 700 bp | 36% | 15.9% |
Alligator mississippiensis | American alligator | 296 MYA | 2089 bp | 76% | 38.4% |
Melopsittacus undulatus | Budgerigar | 296 MYA | 1764 bp | 73% | 40.3% |
Taeniopygia guttata | Zebra finch | 296 MYA | 1980 bp | 75% | 44.2% |
Lepisosteus oculatus | Spotted gar | 400.1 MYA | 1269 bp | 65% | 30.9% |
Saccoglossus kowalevskii | Acorn worm | 661.2 MYA | 2515 bp | 42% | 24.1% |
Branchiostoma floridae | Lancelet | 713.2 YA | 1758 bp | 55% | 27.0% |
Maylandia zebra | Zebra mbuna fish | 400.1 MYA | 4815 bp | 58% | 21.4% |
Trichoplax adhaerens | Trichoplax | 800 MYA | 1605 bp | 56% | 10.3% |
Pelodiscus sinensis | Chinese softshell turtle | 296 MYA | 2895 bp | 77% | 33.9% |
Falco cherrug | Saker falcon | 296 MYA | 1866 bp | 73% | 48.9% |
The most distant homolog detected or predicted is Trichoplax adhaerans. It has a conserved CCDC138 gene and has evolved 800 MYA before the human lineage.
Among the orthologs stated above, there are various homologous regions that are conserved shown in figures below.
Green colors shows completely conserved residues, yellow color shows identical residues, cyan color shows similar residues, white color shows different residues.
The observed phylogeny of the CCDC138 gene of the above mentioned orthologs recapitulates the evolutionary history. [9]
The figure above shows the evolutionary relationship of CCDC138 in the orthologs.
The CCDC138 protein is predated to have a molecular weight of 76.2Kda [10] and an isoelectric point of 8.614. [11] Compositional analysis shows that there is a low usage of the AGP grouping in CCDC138, and there are no positive, negative or mixed charge clusters. The protein has no ER retention motif in the C-terminus and no RNA binding motif. [12] It has also been predicted to be a soluble nuclear protein with a leucine zipper pattern (PS00029) at position 205 onwards with a sequence LQKRERFLLEREQLLFRHENAL. [12]
There are two isoforms of the CCDC138 protein. The primary isoform has 665 amino acids [13] while the secondary isoform has 577 amino acids, [13] and is missing 88 amino acids at the C-terminus.
Figure shows the pairwise sequence alignment comparing the primary isoform (Isoform 1) to the secondary isoform (Isoform 2).
A domain of unknown function (DUF2317) on the protein at location 212 – 315 has been characterized in bacteria. TMHMM [14] and TMAP [15] suggests that there are no predicted transmembrane domain. SOSUI [16] further predicts that CCDC138 is a soluble protein with no transmembrane domain.
According to SUMOplot Analysis Program, [17] there are 7 predicted sumoylation at lysine residues K7, K207, K336, K374, K383, K521, and K591. NetPhos [18] predicts that there are 44 phosphorylations sites, including 29 serine residues, 10 threonine residues, and 5 tyrosine residues. There are no further post-translational modifications as predicted by NetNGlyc, [19] NetOGlyc, [20] SignalP, [21] Sulfinator, [22] and Myristoylator. [23]
The CCDC138 protein contains multiple alpha helixes, beta sheets and coiled-coils as predicted by PELE, CHOFAS, and GOR4.
Yellow shows coiled-coil, blue shows alpha helix, and red shows beta sheet. The majority of the sequence are coiled-coils and alpha helixes.
There are no predicted 3° and 4° Structures for the CCDC138 protein. However, there is a similar structure that has a 29% identity. [24] The predicted structure is Chain A, crystal structure analysis of Clpb, a protein that encodes an ATP-dependent protease and chaperone. This protein has an aligned-length of 144 amino acids, and the alignment is located at the domain of unknown function of CCDC138.
The gene is expressed at low levels in almost all human tissues, but higher levels have been seen in certain cancer tissues. CCDC138 is a soluble protein that is pre diced to localise in the nucleus of a cell.
The promoter region of CCDC138 is shown as figure below.
Microarray-assessed tissue expression patterns through GEO profiles show that CCDC138 is expressed in moderate levels in various tissues including peripheral blood lymphocyte, fetal thymus, thymus, testis, ovary, feral brain, colon, mammary gland, and bone marrow. [25]
There are two most significant alternative transcript variants for CCDC138 mRNA. The first variant as shown in the figure below has been found in lung, blood, and human embryonic stem cells. [26] The second variant has been found in adenocarcinoma, prostate, lung, and primary lung epithelial cells. [27]
First transcript shows the complete mRNA transcript. Second transcript is the first variant, while the thirst transcript is the second variant. [28]
The exact function of CCDC138 is yet to be known.
The CCDC138 protein has been found to interact with ubiquitin C, [29] a protein involved in ubiquination and eventually protein degradation.
The table below shows some transcription factors that have been predicted by Genomatix that binds to the regulatory sequence of the CCDC138 gene. [30]
Detailed family information | Detailed matrix information | Tissue |
---|---|---|
GC-Box factors SP1/GC | Stimulating protein 1, ubiquitous zinc finger transcription factor | Ubiquitous |
Peroxisome proliferator-activated receptor | Peroxisome proliferator-activated receptor gamma, DR1 sites | Adipose Tissue, Connective Tissue, Digestive System, Liver |
MYT1 C2HC zinc finger protein | MyT1 zinc finger transcription factor involved in primary neurogenesis | Central Nervous System, Nervous System, Neuroglia, Neurons |
NGFI-B response elements, nur subfamily of nuclear receptors | Monomers of the nur subfamily of nuclear receptors (nur77, nurr1, nor-1) | Brain, Central Nervous System, Endocrine System, Immune System, Leydig Cells, Nervous System, Neurons, Testis, Thymus Gland, Urogenital System |
Krueppel-like transcription factors | Core promoter-binding protein (CPBP) with 3 Krueppel-type zinc fingers (KLF6, ZF9) | Blood cells, bone marrow cells, digestive system, embryonic structures, Erythrocytes, Hematopoietic System, liver |
Grainyhead-like transcription factors | Grainyhead-like 3 (sister-of-mammalian grainyhead - SOM) | Embryonic Structures, Integumentary System |
CTCF and BORIS gene family, transcriptional regulators with 11 highly conserved zinc finger domains | Insulator protein CTCF (CCCTC-binding factor) | Blood Cells, Embryonic Structures, Endocrine System, Erythrocytes, Germ Cells, Testis, Urogenital System |
Core promoter motif ten elements | Human motif ten element | - |
Abdominal-B type homeodomain transcription factors | Homeobox C13 / Hox-3gamma | Bone Marrow Cells, Bone and Bones, Central Nervous System, Connective Tissue, Embryonic Structures, Hematopoietic System, Integumentary System, Kidney, Nervous System, Neurons, Prostate, Skeleton, Spinal Cord, Urogenital System |
E2F-myc activator/cell cycle regulator | E2F transcription factor 2 | Ubiquitous |
PAX-3 binding sites | Pax-3 paired domain protein, expressed in embryogenesis, mutations correlate to Waardenburg Syndrome | Embryonic structures, muscle, skeletal, muscles |
ZF5 POZ domain zinc finger | ZF5 POZ domain zinc finger, zinc finger protein 161 | - |
Vertebrate TATA binding protein factor | Cellular and viral TATA box elements | - |
CCAAT binding factors | Avian C-type LTR CCAAT box | Ubiquitous |
Ccaat/Enhancer Binding Protein | CCAAT/enhancer binding protein alpha | Adipose Tissue, Bone Marrow Cells, Connective Tissue, Digestive System, Hematopoietic System, Immune System, Liver, Myeloid Cells, Phagocytes |
Activator-, mediator- and TBP-dependent core promoter element for RNA polymerase II transcription from TATA-less promoters | X gene core promoter element 1 | - |
CCDC138 has been identified as one of the many genes involved in initiating term labor in myometrium. [31]
QRICH1, also known as Glutamine-rich protein 1, is a protein that in humans is encoded by the QRICH1 gene. One notable feature of this protein is that it contains a Caspase Activation Recruitment Domain, also known as a CARD domain. As a result of having this domain, QRICH1 is believed to be involved in apoptotic, inflammatory, and host-immune response pathways.
Proline-rich 12 (PRR12) is a protein of unknown function encoded by the gene PRR12.
Coiled-coil domain containing 94 (CCDC94) is a protein that in humans is encoded by the CCDC94 gene. The CCDC94 protein contains a coiled-coil domain, a domain of unknown function (DUF572), an uncharacterized conserved protein (COG5134), and lacks a transmembrane domain.
Transmembrane protein 33 is a protein that in humans, is encoded by the TMEM33 gene, also known as SHINC3. Another name for the TMEM33 protein is DB83.
Coiled Coil Domain Containing protein 42B, also known as CCDC42B, is a protein encoded by the protein-coding gene CCDC42B.
C6orf222 is a protein that in humans is encoded by the C6orf222 gene (6p21.31). C6orf222 is conserved in mammals, birds and reptiles with the most distant ortholog being the green sea turtle, Chelonia mydas. The C6orf222 protein contains one mammalian conserved domain: DUF3293. The protein is also predicted to contain a BH3 domain, which has predicted conservation in distant orthologs from the clade Aves.
The coiled-coil domain containing 142 (CCDC142) is a gene which in humans encodes the CCDC142 protein. The CCDC142 gene is located on chromosome 2, spans 4339 base pairs and contains 9 exons. The gene codes for the coiled-coil domain containing protein 142 (CCDC142), whose function is not yet well understood. There are two known isoforms of CCDC142. CCDC142 proteins produced from these transcripts range in size from 743 to 665 amino acids and contain signals suggesting protein movement between the cytosol and nucleus. Homologous CCDC142 genes are found in many animals including vertebrates and invertebrates but not fungus, plants, protists, archea, or bacteria. Although the function of this protein is not well understood, it contains a coiled-coil domain and a RINT1_TIP1 motif located within the coiled-coil domain.
Chromosome 4 open reading frame 51 (C4orf51) is a protein which in humans is encoded by the C4orf51 gene.
Chromosome 9 open reading frame 50 is a protein that in humans is encoded by the C9orf50 gene. C9orf50 has one other known alias, FLJ35803. In humans the gene coding sequence is 10,051 base pairs long, transcribing an mRNA of 1,624 bases that encodes a 431 amino acid protein.
Single-pass membrane and coiled-coil domain-containing protein 3 is a protein that is encoded in humans by the SMCO3 gene.
WD Repeat and Coiled-coiled containing protein (WDCP) is a protein which in humans is encoded by the WDCP gene. The function of the protein is not completely understood, but WDCP has been identified in a fusion protein with anaplastic lymphoma kinase found in colorectal cancer. WDCP has also been identified in the MRN complex, which processes double-stranded breaks in DNA.
Coiled-coil domain containing 121 (CCDC121) is a protein encoded by the CCDC121 gene in humans. CCDC121 is located on the minus strand of chromosome 2 and encodes three protein isoforms. All isoforms of CCDC121 contain a domain of unknown function referred to as DUF4515 or pfam14988.
TMEM275 is a protein that in humans is encoded by the TMEM275 gene. TMEM275 has two, highly-conserved, helical trans-membrane regions. It is predicted to reside within the plasma membrane or the endoplasmic reticulum's membrane.
FAM120AOS, or family with sequence similarity 120A opposite strand, codes for uncharacterized protein FAM120AOS, which currently has no known function. The gene ontology describes the gene to be protein binding. Overall, it appears that the thyroid and the placenta are the two tissues with the highest expression levels of FAM120AOS across a majority of datasets.
Family with sequence 98, member C or FAM98C is a gene that encodes for FAM98C has two aliases FLJ44669 and hypothetical protein LOC147965. FAM98C has two paralogs in humans FAM98A and FAM98B. FAM98C can be characterized for being a Leucine-rich protein. The function of FAM98C is still not defined. FAM98C has orthologs in mammals, reptiles, and amphibians and has a distant orhtologs in Rhinatrema bivittatum and Nanorana parkeri.
Zinc Finger Protein 548 (ZNF548) is a human protein encoded by the ZNF548 gene which is located on chromosome 19. It is found in the nucleus and is hypothesized to play a role in the regulation of transcription by RNA Polymerase II. It belongs to the Krüppel C2H2-type zinc-finger protein family as it contains many zinc-finger repeats.
THAP domain-containing protein 3 (THAP3) is a protein that, in Homo sapiens (humans), is encoded by the THAP3 gene. The THAP3 protein is as known as MGC33488, LOC90326, and THAP domain-containing, apoptosis associated protein 3. This protein contains the Thanatos-associated protein (THAP) domain and a host-cell factor 1C binding motif. These domains allow THAP3 to influence a variety of processes, including transcription and neuronal development. THAP3 is ubiquitously expressed in H. sapiens, though expression is highest in the kidneys.
Chromosome 13 Open Reading Frame 46 is a protein which in humans is encoded by the C13orf46 gene. In humans, C13orf46 is ubiquitously expressed at low levels in tissues, including the lungs, stomach, prostate, spleen, and thymus. This gene encodes eight alternatively spliced mRNA transcript, which produce five different protein isoforms.
Secernin-3 (SCRN3) is a protein that is encoded by the human SCRN3 gene. SCRN3 belongs to the peptidase C69 family and the secernin subfamily. As a part of this family, the protein is predicted to enable cysteine-type exopeptidase activity and dipeptidase activity, as well as be involved in proteolysis. It is ubiquitously expressed in the brain, thyroid, and 25 other tissues. Additionally, SCRN3 is conserved in a variety of species, including mammals, birds, fish, amphibians, and invertebrates. SCRN3 is predicted to be an integral component of the cytoplasm.
Leucine-rich repeat-containing protein 74A (LRRC74A), is a protein encoded by the LRRC74A gene. The protein LRRC74A is localized in the cytoplasm. It has a calculated molecular weight of approximately 55 kDa. The LRRC74A protein is nominally expressed in the testis, salivary gland, and pancreas.