Biosynthesis and processing of the cell adhesion molecule PECAM-1 includes production of a soluble form
PECAM-1 (CD31) is a 130-kDa glycoprotein found on platelets, endothelial cells, granulocytes, and monocytes, as well as on certain myelomonocytic cell lines. Recent studies have shown that PECAM-1 may be involved in activation of leukocyte integrins and may also be involved in adhesive interactions...
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Published in | The Journal of biological chemistry Vol. 269; no. 25; pp. 17183 - 17191 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Bethesda, MD
American Society for Biochemistry and Molecular Biology
24.06.1994
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Subjects | |
Online Access | Get full text |
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Summary: | PECAM-1 (CD31) is a 130-kDa glycoprotein found on platelets, endothelial cells, granulocytes, and monocytes, as well as on
certain myelomonocytic cell lines. Recent studies have shown that PECAM-1 may be involved in activation of leukocyte integrins
and may also be involved in adhesive interactions of circulating leukocytes and the vessel wall. In spite of the important
functional role that PECAM-1 plays in these processes, little is known about the biosynthesis, processing, and turnover of
PECAM-1 on the cell surface. We have studied the biosynthesis of PECAM-1 in the promonocytic cell line U937, and in endothelial
cells, by pulse-chase labeling and immunoprecipitation. PECAM-1 was synthesized as a 110-kDa precursor form, which was processed
into the 130-kDa mature form within 1-3 h, during which time it began to move to the cell surface. The protein disappeared
from the cell surface in both cell types about 48 h after labeling. A soluble form of PECAM-1, which is 5-10 kDa smaller than
cell-associated PECAM-1 and contains the cytoplasmic tail, was observed in the culture media of HUVECs and phorbol ester-treated
U937 cells. This form of soluble PECAM-1 is encoded by an alternatively spliced mRNA from which the exon containing the transmembrane
domain has been removed. Soluble PECAM-1 was also detected in normal human plasma at levels of 10-25 ng/ml. Two isoforms of
plasma PECAM-1, which differed in the presence of the cytoplasmic tail, were observed by Western blot analysis. In parallel
with soluble forms of other cell adhesion molecules, soluble PECAM-1 may play a role in modulating the inflammatory response. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0021-9258 1083-351X |
DOI: | 10.1016/s0021-9258(17)32538-3 |