"BM180": a novel basement membrane protein with a role in stimulus-secretion coupling by lacrimal acinar cells.
Regulated secretion requires the developmental coupling of neuronal or hormonal stimuli to an exocytotic response, a multistep pathway whose appearance may be linked with cellular adhesion to the newly formed exocrine cell basement membrane. We screened for adhesion-associated coupling activity using lacrimal acinar cells and have identified "BM180", a novel basement membrane protein enriched in guanidine HCl extracts of lacrimal and parotid exocrine secretory glands. BM180 resides primarily in a previously inexamined lower molecular-mass basement membrane peak (peak 2) that contains cell adhesion activity inhibitable with the anti-BM180 monoclonal antibody 3E12. Removal of peak 2 by gel filtration or preincubation of basement membrane with 3E12 decreased regulated peroxidase secretion by one-half without affecting constitutive secretion or the amount of cellular peroxidase available for release. Adding back peak 2 restored regulated secretion in a dose-dependent and 3E12-inhibitable manner and suggested a synergistic relationship between BM180 and laminin 1. BM180 has a mobility of 180 and 60 kDa in the absence or presence of dithiothreitol, respectively, and shows no immunological identity by competitive enzyme-linked immunosorbent assay with laminin 1, collagen IV, entactin, fibronectin, BM-40, perlecan, or vitronectin. We propose that BM180 is an important resident of certain glandular basement membranes where it interacts with the cell surface, thereby possibly signaling the appearance of a transducing element in the stimulus-secretion coupling pathway.
Laurie
G W
GW
Department of Cell Biology, University of Virginia, Charlottesville 22908, USA.
Glass
J D
JD
Ogle
R A
RA
Stone
C M
CM
Sluss
J R
JR
Chen
L
L
D000818:Animals; D000911:Antibodies, Monoclonal; D001485:Basement Membrane / Q000378:metabolism*; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000032:analysis / Q000502:physiology*; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D019791:Guanidine; D006146:Guanidines; D006851:Hydrochloric Acid; D007765:Lacrimal Apparatus / Q000737:chemistry / Q000166:cytology / Q000502:physiology*; D008297:Male; D051379:Mice; D010306:Parotid Gland / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D014020:Tissue Extracts / Q000032:analysis
D000911:Antibodies, Monoclonal; C101023:BM180 protein, mouse; D015815:Cell Adhesion Molecules; D006146:Guanidines; D014020:Tissue Extracts; D019791:Guanidine; D006851:Hydrochloric Acid