TY - JOUR
T1 - Phosphoinositides and phosphoinositide-utilizing enzymes in detergent-insoluble lipid domains
AU - Hope, Heidi Rath
AU - Pike, Linda J.
PY - 1996/6
Y1 - 1996/6
N2 - Recent evidence has implicated caveolae/DIGs in various aspects of signal transduction, a process in which polyphosphoinositides play a central role. We therefore undertook a study to determine the distribution of phosphoinositides and the enzymes that utilize them in these detergent-insoluble domains. We report here that the polyphosphoinositide phosphatase, but not several other phosphoinositide-utilizing enzymes, is highly enriched in a low density, Triton-insoluble membrane fraction that contains caveolin. This fraction is also enriched in polyphosphoinositides, containing approximately one-fifth of the total cellular phosphatidylinositol (4,5)P2. Treatment of cells with the tumor-promoting phorbol ester, phorbol 12-myristate 13-acetate (PMA), did not alter the distribution of polyphosphoinositides or the polyphosphoinositide phosphatase. However, PMA treatment did lead to a decrease in the mitogen-activated protein kinase and actin present in these domains. PMA also induced the recruitment of protein kinase Ca to the caveolae/DIGs fraction. These findings suggest that polyphosphoinositides, the polyphosphoinositide phosphatase and protein kinase C play an important role in the structure or function of detergent-insoluble membrane domains.
AB - Recent evidence has implicated caveolae/DIGs in various aspects of signal transduction, a process in which polyphosphoinositides play a central role. We therefore undertook a study to determine the distribution of phosphoinositides and the enzymes that utilize them in these detergent-insoluble domains. We report here that the polyphosphoinositide phosphatase, but not several other phosphoinositide-utilizing enzymes, is highly enriched in a low density, Triton-insoluble membrane fraction that contains caveolin. This fraction is also enriched in polyphosphoinositides, containing approximately one-fifth of the total cellular phosphatidylinositol (4,5)P2. Treatment of cells with the tumor-promoting phorbol ester, phorbol 12-myristate 13-acetate (PMA), did not alter the distribution of polyphosphoinositides or the polyphosphoinositide phosphatase. However, PMA treatment did lead to a decrease in the mitogen-activated protein kinase and actin present in these domains. PMA also induced the recruitment of protein kinase Ca to the caveolae/DIGs fraction. These findings suggest that polyphosphoinositides, the polyphosphoinositide phosphatase and protein kinase C play an important role in the structure or function of detergent-insoluble membrane domains.
UR - http://www.scopus.com/inward/record.url?scp=0029899011&partnerID=8YFLogxK
U2 - 10.1091/mbc.7.6.843
DO - 10.1091/mbc.7.6.843
M3 - Article
C2 - 8816992
AN - SCOPUS:0029899011
SN - 1059-1524
VL - 7
SP - 843
EP - 851
JO - Molecular biology of the cell
JF - Molecular biology of the cell
IS - 6
ER -