Role of the pro-α2(I) COOH-terminal region in assembly of type I collagen: Truncation of the last 10 amino acid residues of pro-α2(I) chain prevents assembly of type I collagen heterotrimer

✍ Scribed by Ai-lee Lim; Sharon A. Doyle; Gary Balian; Barbara D. Smith

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 325 KB
• Volume: 71
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/(sici)1097-4644(19981101)71:2<216::aid-jcb7>3.0.co;2-y

✦ Synopsis

Procollagen (Type I) contains a noncollagenous COOH-terminal propeptide (C-propeptide) hypothesized to be important in directing chain association and alignment during assembly. We previously expressed human pro-␣2(I) cDNA in rat liver epithelial cells, W8, that produce only pro-␣1(I) trimer collagen Matrix Biol. 14: 21-30). In the resulting cell lines, ␣2(I) assembled with ␣1(I) forming heterotrimers. Using this cell system, we investigated the importance of the COOH-terminal propeptide sequence of the pro-␣2(I) chain for normal assembly of type I collagen. Full-length human pro-␣2(I) cDNA was cloned into expression vectors with a premature stop signal eliminating the final 10 amino acids. No triple-helical molecules containing ␣2(I) were detected in transfected W8 cells, although pro-␣2(I) mRNA was detected. Additional protein analysis demonstrated that these cells synthesize small amounts of truncated pro-␣2(I) chains detected by immunoprecipitation with a pro-␣2(I) antibody. In addition, since the human-rat collagen was less thermostable than normal intraspecies collagen, wild-type and C-terminal truncated mouse cDNAs were expressed in mouse D2 cells, which produced only type I trimers. Results from both systems were consistent, suggesting that the last 10 amino acid residues of the pro-␣2(I) chain are important for formation of stable type I collagen.