Transmembrane protein 217

Genetic protein

Transmembrane Protein 217 is a protein encoded by the gene TMEM217. TMEM217 has been found to have expression correlated with the lymphatic system and endothelial tissues, and has been predicted to have a function linked to the cytoskeleton.[1][2][3]

## Gene

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TMEM217 is located on the chromosome 6 minus strand at 6p21.2.[4] The gene consists of 46,857 base pairs and is flanked by TBC1D22B (TBC1 Domain Family Member 22B) and PIM1.[4][5] It was previously known as C6orf128 (Chromosome 6 open reading frame 128).[4]

## mRNA

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TMEM217 has three common isoforms formed from the alternative splicing of three exons. Isoform 1 translates for the longest polypeptide, consisting of 1590 nucleotides.[6] The 5’ un-translated region of isoform 1 is relatively short and is predicted to fold into several stem loop domains within conserved areas of the un-translated region.[7]

## Protein

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### Primary Protein Sequence

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The longest polypeptide of transmembrane protein 217 consists of 229 amino acids.[8] This protein isoform has a predicted weight of 26.6 kDa and isoelectric point at a pH of 9.3.[9][10] It is notably rich in isoleucine and phenylalanine, and deficient in alanine, aspartate, and proline compared to other proteins.[11] Transmembrane protein 217 contains the domain of unknown function, DUF4534, between amino acids 11-171.[12]

### Secondary Structure

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Transmembrane protein 217 is predicted to have four transmembrane domains.[8][13] These transmembrane domains consist primarily of uncharged amino acids in predicted alpha helices.[11][14] The N-terminus and C-terminus of the protein are predicted to be facing the cytosol with the C-terminus containing a long predicted coiled tail extending from the final transmembrane domain.[13]

### Post-Translational Modifications

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There are several predicted phosphorylation and glycosylation sites on transmembrane protein 217 in highly conserved parts of the protein, where the phosphorylation sites are located primarily on the C-terminal tail.[15][16][17] There are also two highly conserved cysteine residues, which have the potential to form a disulfide bond in the extracellular space between the first and second transmembrane domains.

The image depicts a conceptual diagram of transmembrane protein 217. The protein is given from N-terminus to C-terminus with predicted cellular, transmembrane and extracellular domains present (colored blue, grey, and orange respectively). The most highly conserved predicted post-translational modifications are provided as well. The following predicted post-translational modifications are provided: phosphorylation sites, disulfide bond, and a C-linked mannosylation.

## Expression

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TMEM217 is not ubiquitously expressed. The gene tends to have expression correlated to lymphatic system, vascular/arterial endothelial tissue, and notable expression in the bladder based on expression profiles and microarray analysis.[1][2] Other tissues that have been shown to express TMEM217 include: connective tissues, the liver, mammary glands, the testis, and the cervix.[1] Co-expression analyses have found that TMEM217 was up-regulated in response to mechanical stretch in dermal fibroblast cells and in response to the resveratrol derivative, DMU-212, in vascular endothelial tissues.[3][18]

## Function

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No known function has been attributed to TMEM217, however a co-expression analysis in dermal fibroblasts has predicted the protein to have a potential association with the cytoskeleton.[3]

## Clinical Significance

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Single nucleotide polymorphisms in TMEM217 have been linked to Alzheimer’s disease and diabetic retinopathy.[19][20] TMEM217 was also found to have similar expression patterns as TRPM2, a biomarker linked to breast carcinoma.[21] Expression profiles have also linked elevated TMEM217 expression to bladder cancer and lymphoma.[1]

## Homology

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TMEM217 was found to have orthologs in organisms as early as the scaled fish, which diverged 420 million years ago.[22] Although found in organisms as early as fish and reptiles, TMEM217 has no known orthologs in any bird species.[23][24]

TMEM217 has no known paralogs.

## References

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1. ^ a b c d "EST Profile-TMEM217-Transmembrane Protein 217". National Center for Biotechnology Information. NCBI.[dead link]
2. ^ a b "GEO Profiles-TMEM217". National Center for Biotechnology Information. NCBI.
3. ^ a b c Reichenbach, M.; Reimann, K.; Reuter, H. (2014). "Gene expression in response to cyclic mechanical stretch in primary human dermal fibroblasts". Genomics Data. 2: 335–9\. doi:10.1016/j.gdata.2014.09.010. PMC 4535970. PMID 26484124.
4. ^ a b c "TMEM217 Gene". GeneCards.
5. ^ "TMEM217 Transmembrane Protein 217 [Homo Sapiens (human)]-Gene-NCBI". National Center for Biotechnology Information. NCBI.
6. ^ "Homo Sapiens Transmembrane Protein 217 (TMEM217), Transcript Variant 1, mRNA". National Center for Biotechnology Information. NCBI. 17 September 2018.
7. ^ Zuker, M (2003). "Mfold web server for nucleic acid folding and hybridization prediction". Nucleic Acids Research. 13 (31): 3406–3415\. doi:10.1093/nar/gkg595. PMC 169194. PMID 12824337.
8. ^ a b "Transmembrane Protein 217 Isoform 1 [Homo Sapiens] - Protein - NCBI". National Center for Biotechnology Information. NCBI.
9. ^ Kramer, Jack. "AASTATS". Biology Workbench. San Diego Supercomputer Center.
10. ^ Toldo, Luca. "Isoelectric Point Determination". Biology Workbench. San Diego Supercomputer Center.
11. ^ a b Brendel, V.; Bucher, P.; Nourbakhsh, I.R.; Blaisdell, B.E.; Karlin, S. (1992). "Methods and algorithms for statistical analysis of protein sequences". Proceedings of the National Academy of Sciences. 89 (6): 2002–2006\. Bibcode:1992PNAS...89.2002B. doi:10.1073/pnas.89.6.2002. PMC 48584. PMID 1549558.
12. ^ Marchler-Baur, A.; Bo, Y.; Han, L.; He, J; Lanczycki, C.J. (2017). "CDD/SPARCLE: functional classification of proteins via subfamily domain architectures". Nucleic Acids Research. 45 (D1): D200 – D203. doi:10.1093/nar/gkw1129. PMC 5210587. PMID 27899674.
13. ^ a b "Predict Location of Transmembrane Helices and Location of Intervening Loop Regions". Biology Workbench. San Diego Supercomputer Center.
14. ^ Chou, P. Y.; Fasman, G. D. (1978). "Prediction of the secondary structure of proteins from their amino acid sequence". Advances in Enzymology. 47: 45–148.
15. ^ Blom, N.; Sicheritz, T.; Gupta, R.; Gammeltoft, S.; Brunak, S. (2004). "Prediction of post-translational glycosylation and phosphorylation of proteins from the amino acid sequence". Proteomics. 4 (6): 1633–1649\. doi:10.1002/pmic.200300771. PMID 15174133. S2CID 18810164.
16. ^ "Motif Scan". MyHits. ExPasy.
17. ^ Gupta, R.; Jung, E.; Brunak, S. "Prediction of N-glycosylation sites in human proteins". NetNGlyc 1.0 Server. Center for Biological Sequence Analysis.
18. ^ Miao, Y.; Cui, L.; Chen, Z.; Zhang, L (2016). "Gene expression profiling of DMU-212-induced apoptosis and anti-angiogenesis in vascular endothelial cells". Pharmaceutical Biology. 54 (4): 660–666\. doi:10.3109/13880209.2015.1071414. PMID 26428916.
19. ^ Floudas, C. S.; Um, N.; Kamboh, M. I.; Barmada, M. M.; Visweswaran, S. (2014). "Identifying genetic interactions associated with late-onset Alzheimer's disease". BioData Mining. 7 (1): 35. doi:10.1186/s13040-014-0035-z. PMC 4300162. PMID 25649863.
20. ^ Lin, H.; Huang, Y.; Lin, J.; Wu, J. (2013). "Association of Genes on Chromosome 6, GRIK2, TMEM217 and TMEM63B (Linked to MRPL14) with Diabetic Retinopathy". Ophthalmologica. 229 (1): 54–60\. doi:10.1159/000342616. PMID 23037145. S2CID 20024729.
21. ^ Sumoza-Toledo, A.; Espinoza-Gabriel, M.; Montiel-Condado, D. (2016). "Evaluation of the TRPM2 channel as a biomarker in breast cancer using public databases analysis". Boletín Médico del Hospital Infantil de México. 73 (6): 397–404\. doi:10.1016/j.bmhime.2017.11.038. PMID 29421284.
22. ^ "TimeTree".
23. ^ Altschul, S.F.; Gish, W.; Miller, W.; Meyers, E.W.; Lipman, D.J. (1990). "Basic local alignment search tool". Molecular Biology. 215 (3): 403–410\. doi:10.1006/jmbi.1990.9999. PMID 2231712.
24. ^ Kent, W.J. (2002). "BLAT- the BLAST-like alignment tool". Genome Research. 12 (4): 656–664\. doi:10.1101/gr.229202. PMC 187518. PMID 11932250.