Phosphorylation of smg p21B in rat peritoneal mast cells in association with histamine release inhibition by dibutyryl-cAMP.
IP3 formation and histamine release from rat peritoneal mast cells stimulated by compound 48/80 were dose-dependently inhibited by Bt2cAMP. These inhibitions were restored to the control level in the presence of H-8, a protein kinase A inhibitor. The 22 kDa protein in mast cells was revealed as a markedly phosphorylated protein by incubating with Bt2cAMP, and this phosphorylation was also diminished by H-8. The 22 kDa phosphoprotein of rat mast cells comigrated with phosphorylated smg p21B, purified from human platelets and phosphorylated by protein kinase A in cell-free system, in both one- and two-dimensional PAGE analysis. Moreover, 22 kDa protein in mast cells was identified as smg p21B by immunoblot analysis using an antibody against smg p21B. From the present study, it became clear that smg p21B is phosphorylated by means of protein kinase A system in rat peritoneal mast cells, and it was assumed that phosphorylated smg p21B plays some important role in the suppression of IP3 formation and histamine release from rat peritoneal mast cells.
Izushi
K
K
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Okayama University, Japan.
Shirasaka
T
T
Chokki
M
M
Tasaka
K
K
D000818:Animals; D003994:Bucladesine / Q000494:pharmacology*; D002417:Cattle; D015180:Electrophoresis, Gel, Two-Dimensional; D004789:Enzyme Activation; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006633:Histamine Antagonists / Q000494:pharmacology*; D006801:Humans; D015151:Immunoblotting; D008297:Male; D008407:Mast Cells / Q000378:metabolism*; D010537:Peritoneum / Q000166:cytology; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020668:rap GTP-Binding Proteins
D006633:Histamine Antagonists; D003994:Bucladesine; D011494:Protein Kinases; D019204:GTP-Binding Proteins; D020668:rap GTP-Binding Proteins