The hC/BTLP gene appears to possess all of the important protein domains present in the bone morphogenetic protein (BMP)-1/procollagen C-proteinase (PCP) protein. Members of the astacin family of metalloproteinases, such as BMP-1, have previously been linked to cell differentiation and pattern formation during development through a proposed role in the activation of latent growth factors of the TGF-.beta. superfamily. In addition, recent findings indicate that BMP-1 is identical to PCP, which is a metalloproteinase involved in the synthesis of matrix collagen. This observation suggests that a functional link may exist between astacin metalloproteinases, growth factors and cell differentiation and pattern formation during development, as well as fibrotic processes characterized by the accumulation of matrix collagen.
Nucleotide and amino acid sequence homologues suggest that hC/BTLP, like BMP-1, possesses PCP activity. PCP activity is one of the essential enzymatic steps required for the extracellular production of insoluble collagen fibrils from soluble procollagen. However, mouse mammalian tolloid-like protein is the most closely related homologue of hC/BTIP. Mouse mammalian tolloid-like protein and BMP-1 are distinct gene products with differential tissue distribution. Based on cross-species comparisons, the regulation and distribution of hC/BTIP would be expected to be distinct from BMP-1. Indeed, mouse mammalian tolloid-like protein exhibits a unique tissue distribution when compared to BMP-1. Thus, the selective inhibition of matrix collagen accumulation is important in highly localized fibrotic disorders, e.g., gliosis associated with neurotrauma and ventricular fibrosis associated with congestive heart failure. This indicates that the astacin protein family has an established, proven history as therapeutic targets.
Clearly there is a need for identification and characterization of further members of the astacin protein family which can play a role in preventing, ameliorating or correcting dysfunctions or diseases, including, but not limited to, restenosis, atherosclerosis, congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD), benign prostatic hypertrophy (BPH), nephritis, fibrosis, glomerulonephritis, gliosis, cirrhosis and anomalies of wound healing, such as keloids, among others.