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Phosphopeptide patterns of the ribosomal protein S6 following stimulation of guineapig parotid glands by secretagogues involving either cAMP or calcium as second messenger
Author(s) -
Padel U.,
Kruppa J.,
Jahn R.,
Söling H.-D.
Publication year - 1983
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(83)80427-x
Subject(s) - phosphopeptide , protein kinase a , second messenger system , ribosomal protein s6 , stimulation , calcium , phosphorylation , secretagogue , biology , biochemistry , chemistry , protein phosphorylation , endocrinology , enzyme , organic chemistry
Stimulation of secretion in exocrine cells is associated with the incorporation of up to 3 to 4 phosphates into the ribosomal protein S6. This occurs with secretagogues involving either cAMP or free calcium as second messenger. An analysis of the phosphorylation pattern of S6 from stimulated guineapig parotid glands reveals 3 phosphopeptides (termed A,B,C). The phosphopeptide pattern was identical for cAMP‐ or calcium‐mediated stimulation, whereas phosphorylation of the S6 protein in vitro with catalytic subunit of cAMP‐dependent protein kinase resulted only in the formation of phosphopeptides A and C. Therefore, secretagogue‐mediated phosphorylation is not or not exclusively catalyzed by cAMP‐dependent protein kinase even when cAMP is the second messenger.