HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lamand, S. R. Articles by Bateman, J. F. Search for Related Content PubMed PubMed Citation Articles by Lamand, S. R. Articles by Bateman, J. F. Social Bookmarking                      What's this?

Volume 270, Number 30, Issue of July 28, pp. 17858-17865, 1995
©1995 by The American Society for Biochemistry and Molecular Biology, Inc.

---

The Type I Collagen pro1(I) COOH-terminal Propeptide N-Linked Oligosaccharide
FUNCTIONAL ANALYSIS BY SITE-DIRECTED MUTAGENESIS

(Received for publication, March 20, 1995; and in revised form, May 15, 1995)

From the Orthopaedic Molecular Biology Research Unit, Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville, Victoria 3052, Australia

The C-propeptides of the pro1(I) and pro2(I) chains of type I collagen are each substituted with a single high-mannose N-linked oligosaccharide. Conservation of this motif among the fibrillar collagens has led to the proposal that the oligosaccharide has structural or functional importance, but a role in collagen biosynthesis has not been unambiguously defined. To examine directly the function of the pro1(I) C-propeptide N-linked oligosaccharide, the acceptor Asn residue was changed to Gln by site-directed mutagenesis. In transfected mouse Mov13 and 3T6 cells, unglycosylated mutant pro1(I) folded and assembled normally into trimeric molecules with pro2(I). In biosynthetic pulse-chase experiments mutant pro1(I) were secreted at the same rate as wild-type chains; however, following secretion, the chains were partitioned differently between the cell layer and medium, with a greater proportion of the mutant pro1(I) being released into the medium. This distribution difference was not eliminated by the inclusion of yeast mannan indicating that the high-mannose oligosaccharide itself was not binding to the matrix or the fibroblast surface after secretion. Subtle alterations in the tertiary structure of unglycosylated C-propeptides may have decreased their affinity for a cell-surface component. Further support for a small conformational change in the mutant C-propeptides came from experiments suggesting that unglycosylated pro1(I) chains were cleaved in vitro by the purified C-proteinase slightly less efficiently than wild-type chains. Mutant and normal pro1(I) were deposited with equal efficiency into the 3T6 cell accumulated matrix, thus the reduced cleavage by C-proteinase and altered distribution in the short pulse-chase experiments were not functionally significant in this in vitro extracellular matrix model system.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				T. J. Rentz, F. Poobalarahi, P. Bornstein, E. H. Sage, and A. D. Bradshaw SPARC Regulates Processing of Procollagen I and Collagen Fibrillogenesis in Dermal Fibroblasts J. Biol. Chem., July 27, 2007; 282(30): 22062 - 22071. [Abstract] [Full Text] [PDF]

				K. S. Murthy, J. R. Grider, and G. M. Makhlouf Heterologous desensitization of response mediated by selective PKC-dependent phosphorylation of Gi-1 and Gi-2 Am J Physiol Cell Physiol, October 1, 2000; 279(4): C925 - C934. [Abstract] [Full Text] [PDF]

				J. Fitzgerald, S. R. Lamande, and J. F. Bateman Proteasomal Degradation of Unassembled Mutant Type I Collagen Pro-alpha 1(I) Chains J. Biol. Chem., September 24, 1999; 274(39): 27392 - 27398. [Abstract] [Full Text] [PDF]