Role of laminin-1, collagen IV, and an autocrine factor(s) in regulated secretion by lacrimal acinar cells.
Adhesion to novel basement membrane component BM180 in the presence of laminin-1 promotes stimulus-secretion coupling in lacrimal acinar cells [G. W. Laurie, J. D. Glass, R. A. Ogle, C. M. Stone, J. R. Sluss, and L. Chen. Am. J. Physiol. 270 (Cell Physiol. 39): C1743-C1750, 1996]. The identity of the active laminin-1 site and the possibility that other promoters of coupling are present in the acinar cell microenvironment were probed by use of different substrates, media, neutralizing antibodies and cell numbers. Regulated peroxidase secretion was unaffected by basement membrane coat concentration and was detectable at reduced levels in serum-free medium. Anti-laminin-1 antibodies, particularly against sites in the beta1 and gamma1 chains, but not alpha1 chains, partially suppressed regulated secretion, as did an anti-collagen IV antibody. Without effect were RGD peptide and antibodies against entactin, the beta1-integrin subunit, and several growth factors. Increasing cell number in serum-free medium revealed an unknown, serum-maskable, secretion-enhancing activity with a remarkable specificity for regulated secretion. Stimulus-secretion coupling, therefore, appears to be modulated by several extracellular factors whose relative contributions remain to be determined.
Department of Cell Biology, University of Virginia, Charlottesville, Virginia 22908, USA.
L
L
Chen
J D
JD
Glass
S C
SC
Walton
G W
GW
Laurie
D000818:Animals; D000906:Antibodies / Q000494:pharmacology*; D001285:Atropine / Q000494:pharmacology; D001485:Basement Membrane / Q000502:physiology; D002217:Carbachol / Q000494:pharmacology; D002478:Cells, Cultured; D003094:Collagen / Q000276:immunology / Q000502:physiology*; D016895:Culture Media, Serum-Free; D006133:Growth Substances / Q000276:immunology*; D007765:Lacrimal Apparatus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007797:Laminin / Q000276:immunology / Q000502:physiology*; D008297:Male; D010544:Peroxidases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013666:Tears / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
D000906:Antibodies; D016895:Culture Media, Serum-Free; D006133:Growth Substances; D007797:Laminin; D014660:Vasoactive Intestinal Peptide; D001285:Atropine; D002217:Carbachol; D003094:Collagen; D010544:Peroxidases