The role of the α3(VI) chain in collagen VI assembly. Expression of an ∅3(VI) chain lacking N-terminal modules N10-N7 restores collagen VI assembly, secretion, and matrix deposition in an α3(VI)-deficient cell line

Abstract

Collagen VI is a microfibrillar protein found in the extracellular matrix of virtually all connective tissues. Three genetically distinct subunits, the αI(VI), α2(VI), and α3(VI) chains, associate intracellularly to form triple-helical monomers, which then assemble into disulfide-bonded dimers and tetrameres before secretion. Although sequence considerations suggest that collagen VI monomers composed of all three chains are the most stable isoform, the precise chain composition of collagen VI remains, controversial and alternative assemblies containing only αl(VI) and α2(VI) chains have also been proposed. To address this question directly and study the role of the α3(VI) chain in assembly, ..