1,25-Dihydroxyvitamin D3 targets PKC-betaII but not PKC-alpha to the basolateral plasma membranes of rat colonocytes.
Prior studies by our laboratory have shown that 1, 25-dihydroxyvitamin D3 activated PKC-alpha, but not PKC-delta, -epsilon, or -zeta, in normal rat colonocytes. In the present studies we demonstrate for the first time that this secosteroid also activated PKC-betaII, another DAG- and Ca2+-dependent PKC isoform recently shown to be present in these cells. Moreover, this activation of PKC-betaII by 1,25-dihydroxyvitamin D3 treatment of isolated colonocytes was shown to be lost in cells from vitamin D-deficient rats and, at least partially, restored by repleting these animals with this secosteroid for 7 days. Under basal conditions, the expression of PKC-alpha and -betaII in brush-border membranes was comparable to their respective expression in basolateral plasma membranes of rat colonocytes. In contrast, the expression of PKC-delta was significantly greater in brush-border membranes, whereas PKC-epsilon and -zeta were enriched in the basolateral plasma membranes. Furthermore, 1,25-dihydroxyvitamin D3 specifically induced the translocation of PKC-betaII, but not PKC-alpha, to the basolateral, but not brush-border plasma membranes of rat colonocytes, via a pp60(c-src)-dependent mechanism.
Wali
R K
RK
Department of Medicine, University of Chicago, Chicago, Illinois, 60637, USA.
Bissonnette
M
M
Skarosi
S
S
Khare
S
S
Sitrin
M
M
Brasitus
T A
TA
D000818:Animals; D002117:Calcitriol / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D003106:Colon / Q000166:cytology / Q000201:enzymology*; D004789:Enzyme Activation; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D011493:Protein Kinase C / Q000378:metabolism*; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D051381:Rats; D017207:Rats, Sprague-Dawley; D013379:Substrate Specificity
D007527:Isoenzymes; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D002117:Calcitriol