P. Deng et al., Biological characterization of uncleavable plasma membrane-anchored human macrophage colony-stimulating factor, BIOC BIOP R, 276(1), 2000, pp. 304-311
Citations number
50
Categorie Soggetti
Biochemistry & Biophysics
Journal title
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
The cell-surface form of human macrophage colony-stimulating factor (CSF-1(
256), M-CSF alpha) is a plasma membrane-anchored transmembrane protein from
which the soluble CSF-1 is released by ectodomain proteolytic cleavage. We
have previously generated two forms of cell surface CSF-1 which failed to
undergo the cleavage by deleting residues 161-165 or residues 159-165 in th
e extracellular juxtamembrane region (1). To determine the biologic signifi
cance of the ectodomain cleavage, we compared the biosynthesis and biologic
activities of uncleavable mutant CSF-1 forms with those of the cleavable w
ild-type (WT) CSF-1. We found that the uncleavable CSF-1 forms were able to
accumulate on cell surface at about threefold higher level than the cleava
ble WT CSF-1 did. We further demonstrated that the uncleavable plasma membr
ane-anchored forms of CSF-1 were biologically active in mediating the proli
feration of CSF-1-dependent cells as well as the intercellular adhesion bet
ween CSF-1 receptor-bearing cells and CSF-1 expressing cells. Furthermore,
the adhesive activity of uncleavable CSF-1 forms was about twofold stronger
than that of WT CSF-1, which indicated that the ectodomain cleavage system
plays an important role in regulating the biologic activities of membrane-
anchored CSF-1. (C) 2000 Academic Press.