The major calmodulin-binding protein in rabbit parietal cells is Ca2+/calmodulin-dependent protein kinase II.
Parietal cell secretion can be stimulated by both histaminergic and cholinergic agonists. We have recently found that inhibition of calmodulin-dependent protein kinase II (CaMK II) activity can abolish cholinergic but not histaminergic stimulation of parietal cell secretion (Am. J. Physiol. 262:G118-122). We have investigated the presence of calmodulin-binding proteins and CaMK II in isolated rabbit parietal cells. Calmodulin-binding proteins with apparent molecular masses of 50, 60, 85, 100, and 240 kDa were observed. The major calmodulin-binding species was a 50 kDa band which was enriched in 50,000 g. microsomal membranes. The 50 kDa calmodulin binding comigrated with immunoreactivity for CaMK II. Partial purification of the microsomal CaMK II demonstrated a 250 kDa oligomer. The results demonstrate that CaMK II is the major calmodulin-binding protein in parietal cells and is associated primarily with light microsomal membranes.
Funasaka
M
M
Department of Surgery, Yale University School of Medicine, New Haven, Connecticut.
Fox
L M
LM
Tang
L H
LH
Modlin
I M
IM
Goldenring
J R
JR
D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002148:Calmodulin-Binding Proteins / Q000032:analysis* / Q000276:immunology; D002478:Cells, Cultured; D011494:Protein Kinases / Q000032:analysis* / Q000276:immunology; D011817:Rabbits; D013270:Stomach / Q000737:chemistry* / Q000166:cytology
D002148:Calmodulin-Binding Proteins; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases