Bone Morphogenetic Protein-1 Processes the NH2-terminal Propeptide, and a Furin-like Proprotein Convertase Processes the COOH-terminal Propeptide of pro-α1(V) Collagen

doi:10.1074/jbc.273.42.27511

Bone Morphogenetic Protein-1 Processes the NH₂-terminal Propeptide, and a Furin-like Proprotein Convertase Processes the COOH-terminal Propeptide of pro-α1(V) Collagen*

From the Departments of ^‡Pathology and Laboratory Medicine and ^§Biomolecular Chemistry, University of Wisconsin, Madison, Wisconsin 53706

Abstract

Bone morphogenetic protein-1 (BMP-1) plays key roles in regulating the deposition of vertebrate extracellular matrix; it is the procollagen C-proteinase that processes the major fibrillar collagen types I–III, and it may process prolysyl oxidase to the mature enzyme necessary to the formation of covalent cross-links in collagen and elastic fibers. Type V collagen is a fibrillar collagen of low abundance that is incorporated into and helps regulate the shape and diameter of type I collagen fibrils. Here we show that, in contrast to its action on procollagens I–III, BMP-1 does not cleave the C-propeptide of pro-α1(V) homotrimers. Instead, the single BMP-1-specific cleavage site within pro-α1(V) chains, lies within the large globular N-propeptide. This cleavage site is immediately upstream of a glutamine, thus redefining the specificity of cleavage for BMP-1-like enzymes. It also produces an NH₂ terminus that corresponds to an equivalent NH₂ terminus on the processed matrix form of the similar α1(XI) chain, thus suggesting physiological significance. Cleavage of the C-propeptide occurs efficiently in recombinant pro-α1(V) homotrimers produced in 293-EBNA human embryonic kidney cells, and this cleavage is shown to occur immediately downstream of the sequence RTRR. This is similar to sites cleaved by subtilisin-like proprotein/prohormone convertases and is shown to be specifically cleaved by the recombinant subtilisin-like proprotein/prohormone convertase furin.

Footnotes

↵* This work was supported by National Institutes of Health Grants AR43621 and GM46846 (to D. S. G.) and by a grant from FibroGen Inc., South San Francisco, CA.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¶ Supported by National Institutes of Health Predoctoral Training Grant T32 GM07215 in Molecular Biosciences.
↵‖ To whom correspondence should be addressed: Dept. of Pathology and Laboratory Medicine, University of Wisconsin, 1300 University Ave., Madison, WI 53706. Tel.: 608-262-4676; Fax: 608-265-3301; E-mail:dsgreens{at}facstaff.wisc.edu.
↵2 Y. Imamura, B. M. Steiglitz, and D. S. Greenspan, unpublished observations.
↵3 S. Amano, K. Takahara, D. R. Gerecke, D. L. Hudson, T. Nishiyama, S. Lee, D. E. Birk, B. L. M. Hogan, D. S. Greenspan, and R. E. Burgeson, unpublished observations.
Abbreviations:

N-propeptide

amino-terminal propeptide

C-propeptide

carboxyl-terminal propeptide

C-telopeptide

nonhelical sequence remaining at the carboxyl terminus of a procollagen chain upon cleavage of the C-propeptide

BMP-1

bone morphogenetic protein-1

mTld

mammalian tolloid

DMEM

Dulbecco’s modified Eagle’s medium

PAGE

polyacrylamide gel electrophoresis

SPC

subtilisin-like proprotein convertase

pN

processing intermediate of procollagen chains that contains the N- but not the C-propeptide

pCα1(V)

processing intermediate of pro-α1(V) collagen that retains the C-propeptide but from which part of the N-propeptide has been removed by BMP-1

α1(V) processed pro-α1(V) chain in which the C-propeptide has been removed and part of the N-propeptide has been removed by BMP-1

P1, P2, P1′, P2′, etc., cleavage site residues amino-terminal to (nonprimed) and carboxyl-terminal to (primed) the cleaved bond.
- Received June 29, 1998.
- Revision received July 30, 1998.