Exosomal polycystin-1-interacting protein is a protein that, in humans, is encoded by the EPCIP gene.[6] EPCIP is found on human chromosome 21, and it is thought to be expressed in tissues of the brain and reproductive organs.[7] Additionally, EPCIP is highly expressed in ovarian surface epithelial cells during normal regulation, but is not expressed in cancerous ovarian surface epithelial cells.[7]

EPCIP
Identifiers
AliasesEPCIP, B37, C21orf120, PRED81, chromosome 21 open reading frame 62, C21orf62
External IDsMGI: 1921637; HomoloGene: 49594; GeneCards: EPCIP; OMA:EPCIP - orthologs
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_001162495
NM_001162496
NM_019596

NM_001163695
NM_028905

RefSeq (protein)

NP_001155967
NP_001155968
NP_062542

NP_001157167
NP_083181

Location (UCSC)Chr 21: 32.79 – 32.81 MbChr 16: 91.05 – 91.1 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse
Predicted protein structure of EPCIP. The highest confidence prediction is at the red end of the structure, and the lowest confidence prediction is at the blue end of the structure.
Figure 1.[5]

Gene

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Common aliases of EPCIP are C21orf62, C21orf120, PRED81, and B37.[6] EPCIP is located on chromosome 21 in humans, and is specifically at the q22.11 position.[8] The EPCIP gene is 4132 base pairs in length and contains five exons.[6]

mRNA

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The mRNA sequence of EPCIP in humans has one known isoform. This isoform is called uncharacterized protein C21orf62 isoform X1. This isoform is 458 base pairs, or 104 amino acids, in length, and it is significantly shorter than the most observed sequence of EPCIP in humans. In addition to having an isoform, EPCIP also has splice variants. All splice variants encode the same gene, but the differences in splice variant sequences occur in the 5' untranslated region of the mRNA sequence.[6]

Protein

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General protein characteristics

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The EPCIP protein in humans has a sequence that is 219 amino acids in length.[9] The primary sequence of EPCIP in humans has a molecular weight of 24.9 kDa and an isoelectric point of 8.[10][11] When it's cleavable signal peptide, which spans amino acids 1-19, is removed, it has a molecular weight of 22.8 kDa and an isoelectric point of 7.8.[10][11][12][13]

Protein composition

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EPCIP in humans has higher cysteine and lower valine concentrations than expected compared to other human proteins. This trend, as showed in Table 1, is the same for other mammals. It does not, however, occur in taxa other than mammalia.[14]

Table 1.[14] Unusual amino acid concentrations of EPCIP in humans and orthologs.
Genus and Species Common Name Organism Clade % Cysteine Amino Acid Concentration of Cysteine Compared to Expected % Valine Amino Acid Concentration of Valine Compared to Expected Other Amino Acids with High or Low Concentration Compared to Expected
Homo sapiens Human Mammalia 4.6% High 3.2% Low -
Mus musculus House Mouse Mammalia 4.3% High 3.5% Low Glutamic Acid (1.7%, low)
Canis lupus familiaris Dog Mammalia 4.1% High 2.7% Low Leucine (14.2%, high)
Physeter catodon Sperm Whale Mammalia 4.6% High 4.1% Expected Serine (11.9%, high)
Gallus gallus Chicken Aves 3.1% Expected 6.7% Expected Alanine (2.2%, low)

Glycine (3.1%, low)

Proline (1.8%, low)

Phenylalanine (7.1%, high)

Serine (12.4%, high)

Threonine (9.8%)

Chelonia mydas Green Sea Turtle Reptilia 3.6% Expected 5.8% Expected Alanine (1.8%, low)

Serine (11.2%, high)

Protein structure

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The protein structure of EPCIP in humans consists of a combination of alpha helices and beta sheets.[15][16] Figure 1 shows a predicted structure of the protein.[5]

Post-translational modifications

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EPCIP has a myristoylation site from amino acid 26–31.[17] It has a sumoylation site from amino acid 132–135.[17][18] Additionally, it has a nuclear export signal from amino acid 98-104.[19]

Expression

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Tissue expression

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EPCIP is expressed in human tissues of the brain and reproductive organs.[6]

Expression level

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EPCIP in humans is moderately expressed in the brain, kidneys, pancreas, prostate, testes, and ovaries.[6][20][21]

Regulation of expression

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EPCIP is expressed during blastocyst, fetus, and adult states of human development.[20] It is overexpressed during some tumor states, including pancreatic, gastrointestinal, germ cell, and glioma tumors.[20]

Function

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The specific function of EPCIP in humans is not yet well understood.[6]

Interacting proteins

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EPCIP is thought to potentially interact with nine other proteins.[22] These interactions are shown in Table 2, and they were found through text mining.

Table 2.[22] Proteins with Evidence of Interaction with EPCIP
Protein Full Name Protein Name Symbol Brief Protein Description[6]
BCL2 Interacting Protein Like BNIPL May function as a bridge molecule that promotes cell death.
Thymosin Beta 4, X-linked Pseudogene 4 TMSB4XP4 Potentially influences actin polymerization.
Synovial Sarcoma X Family Member 4 SSX4 May function as a repressor of transcription, and can be useful targets in cancer vaccine-based immunotherapy.
Crystallin Beta A2 CRYBA2 A major protein in vertebrate eyes that maintains lens transparency and reflective index.
Oral Cancer Overexpressed 1 ORAOV1 A gene that is frequently overexpressed in esophageal squamous cell cancer.
Oligodendrocyte Transcription Factor 1 OLIG1 May be expressed during the time from process extension through membrane maintenance in oligodendrocytes.
PAX3 and PAX7 Binding Protein 1 GCFC1 (PAXBP1) The encoded protein potentially binds to GC-rich DNA sequences. It is suggested that this gene is involved in the regulation of transcription.
Relaxin/Insulin Like Family Peptide Receptor 1 and 2 RXFP1 and RXFP2 Encoded protein is a receptor for the protein hormone relaxin that influences sperm motility and pregnancy.

Clinical significance

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EPCIP over or under expression is linked to some types of cancerous cells and tumors.[7][20]

Homology

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Paralogs

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There are no known paralogs of EPCIP in humans at this time.[6]

Orthologs

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There are currently 193 organisms that are known to be orthologs of EPCIP.[6] The orthologs of EPCIP are deuterostome animals in the clade Chordata.[6] Table 3 shows a range of EPCIP orthologs, their NCBI accession numbers, sequence lengths, and sequence identity to the EPCIP human protein. At this time, EPCIP is not known to have any protostome or invertebrate orthologs.[6]

Table 3. Orthologs of Human Protein EPCIP
Genus and Species Common Name Organism Clade Estimated Date of Divergence from Humans (Millions of Years Ago)[23] Accession Number[9] Amino Acid Sequence Length[9] Corrected Sequence Identity to Human Protein[24][25]
Homo sapiens Human mammalia 0 NP_001155967.2 219 100%
Mus musculus House Mouse mammalia 90 NP_083181.1 230 68.2%
Meleagris gallopavo Wild Turkey aves 312 XP_010721230.1 225 56.4%
Chelonia mydas Green Sea Turtle reptilia 312 XP_007063646.1 224 60.8%
Xenopus tropicalis Western Clawed Frog tetrapoda 352 NP_001004889.1 207 48.9%
Latimeria chalumnae West Indian Ocean Coelacanth sarcopterygii 413 XP_005993681.2 237 45.0%
Ictalurus punctatus Channel Catfish actinopterygii 435 XP_017326002.1 214 29.6%
Callorhinchus milii Australian Ghostshark condrichthyes 473 XP_007904174.1 222 40.4%
 
Figure 2.[9] Evolution of EPCIP in humans over time.

Evolution rate

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EPCIP has an evolution rate that is faster than cytochrome C and fibrinogen. Figure 2 shows the rate of evolution of the EPCIP gene over the past 473 million years.

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References

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  1. ^ a b c ENSG00000205929 GRCh38: Ensembl release 89: ENSG00000262938, ENSG00000205929Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000039851Ensembl, 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. ^ a b Kelley L. "PHYRE2 Protein Fold Recognition Server". www.sbg.bio.ic.ac.uk. Retrieved 2017-05-07.
  6. ^ a b c d e f g h i j k l "EPCIP exosomal polycystin 1 interacting protein [ Homo sapiens (human) ]". www.ncbi.nlm.nih.gov. Retrieved 2024-05-15.
  7. ^ a b c "Home - GEO Profiles - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2017-05-07.
  8. ^ Database GH. "C21orf62 Gene - GeneCards | CU062 Protein | CU062 Antibody". www.genecards.org. Retrieved 2017-05-07.
  9. ^ a b c d "Protein". www.ncbi.nlm.nih.gov. Retrieved 2017-05-07.
  10. ^ a b Kramer J (1990). "AASTATS". Biology Workbench.
  11. ^ a b Toldo L. "PI Isoelectric Point Determination Program". Biology Workbench.
  12. ^ "PSORT II server - GenScript". www.genscript.com. Retrieved 2017-05-07.
  13. ^ Charpilloz JL. "TERMINUS - Welcome to terminus". terminus.unige.ch. Retrieved 2017-05-07.
  14. ^ a b Brendel V (1992). "Statistical Analysis of PS". Biology Workbench. Archived from the original on 2003-08-11. Retrieved 2017-02-06.
  15. ^ Pearson WR (September 1998). "CHOFAS Analysis". Biology Workbench. Archived from the original on 2003-08-11. Retrieved 2017-02-06.
  16. ^ Pappas GJ Jr (1974–1996). "PELE: Protein Structure Prediction". Biology Workbench. Archived from the original on 2003-08-11. Retrieved 2017-02-06.
  17. ^ a b "Motif Scan". myhits.isb-sib.ch. Retrieved 2017-05-07.
  18. ^ The Cucko Workgroup (May 1, 2017). "GPS-SUMO 2.0 Online Service". sumosp.biocuckoo.org/online.php. Archived from the original on February 17, 2019. Retrieved May 5, 2017.
  19. ^ la Cour T, Kiemer L, Mølgaard A, Gupta R, Skriver K, Brunak S (2004). "Analysis and prediction of leucine-rich nuclear export signals". Protein Eng. Des. Sel. 17 (6): 527–36. doi:10.1093/protein/gzh062. PMID 15314210.
  20. ^ a b c d "Home - UniGene - NCBI". www.ncbi.nlm.nih.gov. Retrieved 2017-05-07.
  21. ^ "The Human Protein Atlas". www.proteinatlas.org. Retrieved 2017-05-07.
  22. ^ a b "STRING: functional protein association networks". string-db.org. Retrieved 2017-05-07.
  23. ^ "TimeTree :: The Timescale of Life". timetree.org. Retrieved 2017-05-07.
  24. ^ "BLAST: Basic Local Alignment Search Tool". blast.ncbi.nlm.nih.gov. Retrieved 2017-05-07.
  25. ^ Myers EW, Miller W (March 1988). "Optimal alignments in linear space". Computer Applications in the Biosciences. 4 (1): 11–17. doi:10.1093/bioinformatics/4.1.11. S2CID 8140207.