TY - JOUR
T1 - Phosphatidylinositol phosphate 5-kinase Iβ recruits AP-2 to the plasma membrane and regulates rates of constitutive endocytosis
AU - Padrón, David
AU - Wang, Ying Jie
AU - Yamamoto, Masaya
AU - Yin, Helen
AU - Roth, Michael G.
PY - 2003/8/18
Y1 - 2003/8/18
N2 - Overexpression of phosphatidylinositol phosphate 5-kinase (PIP5KI) isoforms α, β, or γ in CV-1 cells increased phosphatidylinositol 4,5-bisphosphate (PIP2) levels by 35, 180, and 0%, respectively. Endocytosis of transferrin receptors, association of AP-2 proteins with membranes, and the number of clathrin-coated pits at the plasma membrane increased when PIP2 increased. When expression of PIP5KIβ was inhibited with small interference RNA in HeLa cells, expression of PIP5KIα was also reduced slightly, but PIP5KIγ expression was increased. PIP2 levels and internalization of transferrin receptors dropped 50% in these cells; thus, PIP5KIγ could not compensate for loss of PIP5KIβ. When expression of PIP5KIα was reduced, expression of both PIP5KIβ and PIP5KIγ increased and PIP2 levels did not change. A similar increase of PIP5KIα and PIP5KIβ occurred when PIP5KIγ was inhibited. These results indicate that constitutive endocytosis in CV-1 and HeLa cells requires (and may be regulated by) PIP2 produced primarily by PIP5KIβ.
AB - Overexpression of phosphatidylinositol phosphate 5-kinase (PIP5KI) isoforms α, β, or γ in CV-1 cells increased phosphatidylinositol 4,5-bisphosphate (PIP2) levels by 35, 180, and 0%, respectively. Endocytosis of transferrin receptors, association of AP-2 proteins with membranes, and the number of clathrin-coated pits at the plasma membrane increased when PIP2 increased. When expression of PIP5KIβ was inhibited with small interference RNA in HeLa cells, expression of PIP5KIα was also reduced slightly, but PIP5KIγ expression was increased. PIP2 levels and internalization of transferrin receptors dropped 50% in these cells; thus, PIP5KIγ could not compensate for loss of PIP5KIβ. When expression of PIP5KIα was reduced, expression of both PIP5KIβ and PIP5KIγ increased and PIP2 levels did not change. A similar increase of PIP5KIα and PIP5KIβ occurred when PIP5KIγ was inhibited. These results indicate that constitutive endocytosis in CV-1 and HeLa cells requires (and may be regulated by) PIP2 produced primarily by PIP5KIβ.
KW - Clathrin
KW - Endocytosis
KW - Phosphatidylinositol 4,5-bisphosphate
KW - Phosphatidylinositol kinase
KW - Transferrin receptor
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UR - http://www.scopus.com/inward/citedby.url?scp=0041976972&partnerID=8YFLogxK
U2 - 10.1083/jcb.200302051
DO - 10.1083/jcb.200302051
M3 - Article
C2 - 12913109
AN - SCOPUS:0041976972
SN - 0021-9525
VL - 162
SP - 693
EP - 701
JO - Journal of Cell Biology
JF - Journal of Cell Biology
IS - 4
ER -