SSR4 explained

Translocon-associated protein subunit delta is a protein that in humans is encoded by the SSR4 gene.^{[1] [2]}

SSR4, also called TRAPD, is assumed to be involved in protein secretion. It is located in the Xq28 region, arranged in a compact head-to-head manner with the IDH3G gene. These two genes are driven by a bidirectional promoter located between them and encode proteins involved in unrelated biochemical pathways located in different compartments of the cell. The nontranscribed intergenic region represents only 133 bp and is embedded in a CpG island. The CpG island functions as a bidirectional promoter to initiate the transcription of both functionally unrelated genes with distinct expression patterns. SSR4 consists of six exons and is approximately 70 kb telomeric length from the ALD gene. Although alternative splicing of exon 5 has not been detected in the human SSR4 gene, transcript variants missing the region homologous to the human exon 5 have been detected in both Xenopus laevis and Mus musculus.

Further reading

• Holthuis JC, van Riel MC, Martens GJ . Translocon-associated protein TRAP delta and a novel TRAP-like protein are coordinately expressed with pro-opiomelanocortin in Xenopus intermediate pituitary . Biochem. J. . 312 (Pt 1) . Pt 1. 205–13 . 1996 . 7492314 . 10.1042/bj3120205. 1136246 .
• Hartmann E, Görlich D, Kostka S, etal . A tetrameric complex of membrane proteins in the endoplasmic reticulum . Eur. J. Biochem. . 214 . 2 . 375–81 . 1993 . 7916687 . 10.1111/j.1432-1033.1993.tb17933.x . 11858/00-001M-0000-0015-3BD2-F . free .
• Wang L, Dobberstein B . Oligomeric complexes involved in translocation of proteins across the membrane of the endoplasmic reticulum . FEBS Lett. . 457 . 3 . 316–22 . 1999 . 10471800 . 10.1016/S0014-5793(99)01075-3 . free .
• Hartley JL, Temple GF, Brasch MA . DNA Cloning Using In Vitro Site-Specific Recombination . Genome Res. . 10 . 11 . 1788–95 . 2001 . 11076863 . 10.1101/gr.143000 . 310948 .
• Strausberg RL, Feingold EA, Grouse LH, etal . Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences . Proc. Natl. Acad. Sci. U.S.A. . 99 . 26 . 16899–903 . 2003 . 12477932 . 10.1073/pnas.242603899 . 139241 . 2002PNAS...9916899M . free .
• Miyazaki K, Fujita T, Ozaki T, etal . NEDL1, a novel ubiquitin-protein isopeptide ligase for dishevelled-1, targets mutant superoxide dismutase-1 . J. Biol. Chem. . 279 . 12 . 11327–35 . 2004 . 14684739 . 10.1074/jbc.M312389200 . free .
• Ota T, Suzuki Y, Nishikawa T, etal . Complete sequencing and characterization of 21,243 full-length human cDNAs . Nat. Genet. . 36 . 1 . 40–5 . 2004 . 14702039 . 10.1038/ng1285 . free .
• Wang Z, VandeBerg JL . Cloning and molecular characterization of a human ortholog of Monodelphis TRAPD in ultraviolet B-induced melanoma . Melanoma Res. . 14 . 2 . 107–14 . 2005 . 15057039 . 10.1097/00008390-200404000-00005 . 12281868 .
• Gerhard DS, Wagner L, Feingold EA, etal . The Status, Quality, and Expansion of the NIH Full-Length cDNA Project: The Mammalian Gene Collection (MGC) . Genome Res. . 14 . 10B . 2121–7 . 2004 . 15489334 . 10.1101/gr.2596504 . 528928 .
• Wiemann S, Arlt D, Huber W, etal . From ORFeome to Biology: A Functional Genomics Pipeline . Genome Res. . 14 . 10B . 2136–44 . 2004 . 15489336 . 10.1101/gr.2576704 . 528930 .
• Mehrle A, Rosenfelder H, Schupp I, etal . The LIFEdb database in 2006 . Nucleic Acids Res. . 34 . Database issue . D415–8 . 2006 . 16381901 . 10.1093/nar/gkj139 . 1347501 .
• Ewing RM, Chu P, Elisma F, etal . Large-scale mapping of human protein–protein interactions by mass spectrometry . Mol. Syst. Biol. . 3 . 1. 89 . 2007 . 17353931 . 10.1038/msb4100134 . 1847948 .

Notes and References

1. Brenner V, Nyakatura G, Rosenthal A, Platzer M . Genomic organization of two novel genes on human Xq28: compact head to head arrangement of IDH gamma and TRAP delta is conserved in rat and mouse . Genomics . 44 . 1 . 8–14 . Nov 1997 . 9286695 . 10.1006/geno.1997.4822 .
2. Web site: Entrez Gene: SSR4 signal sequence receptor, delta (translocon-associated protein delta).