Identification of caveolin-1 in lipoprotein particles secreted by exocrine cells.
Caveolin-1 is a protein component (of relative molecular mass 22, 000) of the striated coat that decorates the cytoplasmic surface of caveolae membranes. Previous biochemical and molecular tests have indicated that caveolin-1 is an integral membrane protein that is co-translationally inserted into endoplasmic-reticulum membranes of fibroblast and epithelial cells such that its carboxy- and amino-terminal ends are in the cytoplasm. Here we identify caveolin-1 in the secretory pathway of exocrine cells. Secretion of caveolin-1 from pancreatic acinar cells and a transfected exocrine cell line, but not from Chinese hamster ovary cells, is stimulated by the secretagogues secretin, cholecystokinin and dexamethasone. The secreted caveolin-1 co-fractionates with apolipoproteins, indicating that it may be secreted in a complex with lipids.
Liu
P
P
Department of Cell Biology and Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75235-9039, USA.
Li
W P
WP
Machleidt
T
T
Anderson
R G
RG
D000818:Animals; D001053:Apolipoproteins / Q000737:chemistry / Q000378:metabolism*; D016466:CHO Cells; D051242:Caveolin 1; D022461:Caveolins; D006224:Cricetinae; D006801:Humans; D008565:Membrane Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D010179:Pancreas / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014162:Transfection
D001053:Apolipoproteins; C495540:CAV1 protein, human; C495541:Cav1 protein, mouse; C495537:Cav1 protein, rat; D051242:Caveolin 1; D022461:Caveolins; D008565:Membrane Proteins