Multiple bone morphogenetic protein 1-related mammalian metalloproteinases process pro-lysyl oxidase at the correct physiological site and control lysyl oxidase activation in mouse embryo fibroblast cultures

J Biol Chem. 2001 Jun 22;276(25):22537-43. doi: 10.1074/jbc.M102352200. Epub 2001 Apr 19.

Abstract

Lysyl oxidase catalyzes the final enzymatic step required for collagen and elastin cross-linking in extracellular matrix biosynthesis. Pro-lysyl oxidase is processed by procollagen C-proteinase activity, which also removes the C-propeptides of procollagens I-III. The Bmp1 gene encodes two procollagen C-proteinases: bone morphogenetic protein 1 (BMP-1) and mammalian Tolloid (mTLD). Mammalian Tolloid-like (mTLL)-1 and -2 are two genetically distinct BMP-1-related proteinases, and mTLL-1 has been shown to have procollagen C-proteinase activity. The present study is the first to directly compare pro-lysyl oxidase processing by these four related proteinases. In vitro assays with purified recombinant enzymes show that all four proteinases productively cleave pro-lysyl oxidase at the correct physiological site but that BMP-1 is 3-, 15-, and 20-fold more efficient than mTLL-1, mTLL-2, and mTLD, respectively. To more directly assess the roles of BMP-1 and mTLL-1 in lysyl oxidase activation by connective tissue cells, fibroblasts cultured from Bmp1-null, Tll1-null, and Bmp1/Tll1 double null mouse embryos, thus lacking BMP-1/mTLD, mTLL-1, or all three enzymes, respectively, were assayed for lysyl oxidase enzyme activity and for accumulation of pro-lysyl oxidase and mature approximately 30-kDa lysyl oxidase. Wild type cells or cells singly null for Bmp1 or Tll1 all produced both pro-lysyl oxidase and processed lysyl oxidase at similar levels, indicating apparently normal levels of processing, consistent with enzyme activity data. In contrast, double null Bmp1/Tll1 cells produced predominantly unprocessed 50-kDa pro-lysyl oxidase and had lysyl oxidase enzyme activity diminished by 70% compared with wild type, Bmp1-null, and Tll1-null cells. Thus, the combination of BMP-1/mTLD and mTLL-1 is shown to be responsible for the majority of processing leading to activation of lysyl oxidase by murine embryonic fibroblasts, whereas in vitro studies identify pro-lysyl oxidase as the first known substrate for mTLL-2.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Bone Morphogenetic Protein 1
  • Bone Morphogenetic Proteins / metabolism*
  • Cells, Cultured
  • Embryo, Mammalian / cytology
  • Embryo, Mammalian / enzymology*
  • Enzyme Activation
  • Enzyme Precursors / metabolism*
  • Fibroblasts / cytology
  • Fibroblasts / enzymology
  • Humans
  • Metalloendopeptidases / metabolism*
  • Mice
  • Protein Processing, Post-Translational*
  • Protein-Lysine 6-Oxidase / metabolism*
  • Recombinant Proteins / metabolism

Substances

  • Bone Morphogenetic Proteins
  • Enzyme Precursors
  • Recombinant Proteins
  • Protein-Lysine 6-Oxidase
  • Metalloendopeptidases
  • BMP1 protein, human
  • Bmp1 protein, mouse
  • Bone Morphogenetic Protein 1