Distribution and relative levels of expression of the phosphoinositidase-C-linked G-proteins Gq alpha and G11 alpha: absence of G11 alpha in human platelets and haemopoietically derived cell lines.
Membranes of a variety of clonal cell lines, including neuroblastoma x glioma hybrid NG108-15, glioma C6, Rat 1 and CHO fibroblasts and the pituitary-derived cell lines alpha T3 and GH3 were immunoblotted with an antiserum (CQ) raised against a synthetic peptide corresponding to the C-terminal decapeptide of the alpha subunits of the phosphoinositidase-C-linked G-proteins Gq and G11. In SDS-PAGE conditions able to resolve these two polypeptides, direct evidence was obtained for co-expression of these two G-proteins in all of the above cell lines. The ratio of these two G-proteins varied substantially (alpha 11/alpha q = 0.25-2.5) between the cell lines. In human platelets and in a range of haemopoietically derived human cell lines including U937 (monoblasts), Raji (Burkitts lymphoma) and Jurkat (mature T cell) expression of G11 alpha was not detected. This was not due to the inability of the antiserum to identify human G11 alpha as other human cell lines co-expressed both G-proteins. A third, unidentified CQ reactive polypeptide of similar mobility was resolved and present in all cell lines examined.
Milligan
G
G
Department of Biochemistry, University of Glasgow, UK.
Mullaney
I
I
McCallum
J F
JF
D000818:Animals; D001792:Blood Platelets / Q000378:metabolism*; D002460:Cell Line / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000032:analysis* / Q000502:physiology; D015870:Gene Expression; D006801:Humans; D054801:Phosphoinositide Phospholipase C; D010727:Phosphoric Diester Hydrolases / Q000032:analysis*; D014407:Tumor Cells, Cultured / Q000378:metabolism
D010727:Phosphoric Diester Hydrolases; D054801:Phosphoinositide Phospholipase C; D019204:GTP-Binding Proteins