A mannose receptor mediates mannosyl-rich glycoprotein-induced mitogenesis in bovine airway smooth muscle cells.
J Clin Invest
; 94(5): 1855-63, 1994 Nov.
Article
in En
| MEDLINE
| ID: mdl-7962531
ABSTRACT
The putative mannose receptor (MR), previously implicated in mannosyl-rich glycoprotein-induced mitogenesis in bovine airway smooth muscle (ASM) cells, was studied to determine its properties. Specific binding of the mitogenic neoglycoprotein, mannosylated bovine serum albumin (Man-BSA) to ASM cells was saturable, with an apparent Kd = 5.0 x 10(-8) M. Cell-bound ManBSA-colloidal gold conjugate was localized by electron microscopy to clathrin-coated pits on the cell surface, and was found to undergo internalization to endosomes; this was inhibitable by weak bases and swainsonine, that also inhibited ligand-induced mitogenesis. The ASM-MR, isolated by mannose-affinity chromatography, had the same apparent molecular mass as the macrophage (Mø) MR (M(r) = 175 kD), and was immunoprecipitated by an anti-MøMR immune serum. This antiserum blocked 125I-labeled-ManBSA binding to intact ASM cells, stimulated mitogenesis, and immunolocalized the ASM-MR in cytoplasmic vesicles compatible with endosomes. A monoclonal antibody directed against the MøMR also reacted with the ASM-MR; like the polyclonal antibodies, it stimulated mitogenesis as effectively as beta-hexosaminidases. These data indicate that the ASM-MR shares a number of functional and structural properties with the MøMR and suggest that similar receptors may have different main functions in different cells.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Trachea
/
Glycoproteins
/
Receptors, Cell Surface
/
Lectins, C-Type
/
Mannose-Binding Lectins
/
Muscle, Smooth
Limits:
Animals
Language:
En
Journal:
J Clin Invest
Year:
1994
Document type:
Article