The cytoplasmic domain of alpha 6A integrin subunit is an in vitro substrate for protein kinase C.
We have investigated whether the cytoplasmic domain of alpha 6A integrin subunit can be phosphorylated by Ser/Thr kinases using synthetic peptides as in vitro substrates. This domain was phosphorylated by protein kinase C (PKC) and cyclic AMP-dependent kinase (protein kinase A, PKA) but not by mitogen-activated protein kinase. While Ser1041 has been shown to be phosphorylated in PMA-stimulated cells in vitro, Ser1048 was phosphorylated by PKA. Furthermore pharmacological agents which induce a rise in cyclic AMP concentration failed to stimulate the phosphorylation of the alpha 6A cytoplasmic domain in intact cells. These results suggest that PKC, but not PKA, is involved in the physiological phosphorylation of the alpha 6A integrin subunit.
Gimond
C
C
The Netherlands Cancer Institute, Division of Cell Biology, Amsterdam.
de Melker
A
A
Aumailley
M
M
Sonnenberg
A
A
D000595:Amino Acid Sequence; D003593:Cytoplasm / Q000378:metabolism*; D039121:Integrin alpha6beta1; D016023:Integrins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012694:Serine / Q000378:metabolism; D013379:Substrate Specificity
D039121:Integrin alpha6beta1; D016023:Integrins; D010455:Peptides; D012694:Serine; D017346:Protein Serine-Threonine Kinases; D011493:Protein Kinase C