Phosphorylation of the band 4.1-like proteins of the bovine lens.
Crude membrane fractions prepared from the superficial cortical fiber cells of bovine lenses were incubated with [gamma-32P]-ATP. Membrane-associated 4.1-like proteins were then immunoprecipitated and analyzed for 32P-incorporation. Band 4.1-like proteins of 150 kd, 80 kd, and 78 kd were found to be labeled in a time-dependent fashion, with the 150 kd protein incorporating label at an 8-fold greater rate than the 80 kd and 78 kd proteins. Addition of cAMP or Ca2+ to the membrane preparations stimulated the phosphorylation of all three of these proteins. Our results indicate that the 4.1-like proteins of the lens fiber cell share with band 4.1 of the RBC the characteristic of being substrates for cAMP-independent and cAMP-dependent protein kinases.
Aster
J C
JC
Brinn
K
K
Maisel
H
H
Brewer
G J
GJ
D000818:Animals; D001345:Autoradiography; D001798:Blood Proteins / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology; D002417:Cattle; D011232:Chemical Precipitation; D003459:Crystallins / Q000378:metabolism*; D000242:Cyclic AMP / Q000494:pharmacology; D003598:Cytoskeletal Proteins; D004789:Enzyme Activation / Q000187:drug effects; D007120:Immunochemistry; D007908:Lens, Crystalline / Q000378:metabolism*; D008565:Membrane Proteins; D009479:Neuropeptides; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism
D001798:Blood Proteins; D003459:Crystallins; D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; D009479:Neuropeptides; C028841:erythrocyte membrane band 4.1 protein; C120557:erythrocyte membrane protein band 4.1-like 1; D000242:Cyclic AMP; D011494:Protein Kinases; D002118:Calcium