title: Protein kinase Calpha can undergo membrane localization via an alternative phosphatidylinositol 4,5-bisphosphate-dependent pathway.
abstract: Protein kinase Calpha (PKCalpha) activation is known to be dependent on the metabolic product of phosphatidylinositol 4,5-bisphosphate (PIP2) by phospholipase C (PLC). Here we report that fibroblasts may have an additional PIP2-dependent mechanism for membrane localization of PKCalpha. We observed PKCalpha membrane localization in both wild type and PLCgamma1 -/- mouse embryonic fibroblasts. Treatment of cells with a specific PLC inhibitor U73122 resulted in increased PIP2 levels and enhanced membrane localization of PKCalpha. PKCalpha levels in the membrane fraction decreased following incubation with PLCgamma, but increased following treatment with U73122 or addition of exogenous PIP2 in vitro. In addition, PKCalpha interacted with PIP2-conjugate bead and mixed micelles containing PIP2. Finally, we found that PIP2 is involved in syndecan-4-mediated membrane localization of PKCalpha. Taken together, these data suggest that PIP2 might contribute to directly regulating the membrane localization of PKCalpha.
authors.affiliation: Department of Life Sciences, Division of Molecular Life Sciences and Center for Cell Signaling Research, Ewha Womans University, Daehyun-dong, Seodaemoon-Gu, Seoul, Republic of Korea.
authors.forename: Hyowon
authors.initials: H
authors.lastname: Son
authors.forename: Yangmi
authors.initials: Y
authors.lastname: Lim
authors.forename: Jinsook
authors.initials: J
authors.lastname: Kim
authors.forename: Haein
authors.initials: H
authors.lastname: Park
authors.forename: Sojoong
authors.initials: S
authors.lastname: Choi
authors.forename: Innoc
authors.initials: I
authors.lastname: Han
authors.forename: Won-Seok
authors.initials: WS
authors.lastname: Kim
authors.forename: Sungsu
authors.initials: S
authors.lastname: Park
authors.forename: Yunsoo
authors.initials: Y
authors.lastname: Bae
authors.forename: Eok-Soo
authors.initials: ES
authors.lastname: Oh
mesh_terms: D000818:Animals; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism*; D002522:Chlorocebus aethiops; D005347:Fibroblasts / Q000378:metabolism*; D051379:Mice; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D051571:Protein Kinase C-alpha / Q000378:metabolism*; D051381:Rats; D015398:Signal Transduction / Q000502:physiology*; D013347:Subcellular Fractions / Q000378:metabolism*
chemical_list: D019269:Phosphatidylinositol 4,5-Diphosphate; D051571:Protein Kinase C-alpha