Phosphatidylinositol 4,5-bisphosphate competitively inhibits phorbol ester binding to protein kinase C

Chauhan, Abha; Chauhan, Ved; Deshmukh, Diwakar S.; Brockerhoff, H.

doi:10.1021/bi00438a007

Cited by 40 publications

(17 citation statements)

References 59 publications

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“…Calcium Dependence of Activation-Since PKC␣␤␥ are known as calcium-dependent enzymes and PIP 2 interacts with PKC through its regulatory domain (18,34), we investigated whether calcium affected the increased activity of PKC␣␤␥ in the presence of PIP 2 and IP 6 (Fig. 2).…”

Section: Pip 2 and Ipmentioning

confidence: 99%

Syndecan-4 Proteoglycan Cytoplasmic Domain and Phosphatidylinositol 4,5-Bisphosphate Coordinately Regulate Protein Kinase C Activity

Oh¹,

Woods²,

Lim³

et al. 1998

Journal of Biological Chemistry

177

151

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Phosphatidylinositol 4,5-bisphosphate (PIP 2 ) is involved in the organization of the actin cytoskeleton by regulating actin-associated proteins. The transmembrane heparan sulfate proteoglycan syndecan-4 also plays a critical role in protein kinase C (PKC) signaling in the formation of focal adhesions and actin stress fibers. The cytoplasmic domain of syndecan-4 core protein directly interacts with and potentiates PKC␣ activity, and it can directly interact with the phosphoinositide PIP 2 . We, therefore, investigated whether the interaction of inositol phosphates and inositol phospholipids with syndecan-4 could regulate PKC activity. Data from in vitro kinase assays using purified PKC␣␤␥ show that in the absence of phosphatidylserine and diolein, PIP 2 increased the extent of autophosphorylation of PKC␣␤␥ and partially activated it to phosphorylate both histone III-S and an epidermal growth factor receptor peptide. This activity was dose-dependent, and its calcium dependence varied with PKC isotype/source. Addition of the cytoplasmic syndecan-4 peptide, but not equivalent syndecan-1 or syndecan-2 peptides, potentiated the partial activation of PKC␣␤␥ by PIP 2 , resulting in activity greater than that observed with phosphatidylserine, diolein, and calcium. This study indicates that syndecan-4 cytoplasmic domain may bind both PIP 2 and PKC␣, localize them to forming focal adhesions, and potentiate PKC␣ activity there.The control of cellular adhesion status is complex, involving several signaling mechanisms (1-4). Phosphatidylinositol 4,5-bisphosphate (PIP 2 ) 1 plays important roles in the organization of the actin cytoskeleton. PIP 2 may control actin polymerization by regulating the binding of actin-binding proteins such as profilin and gelsolin to actin (5, 6). PIP 2 may also interact with ␣-actinin and vinculin (7) and regulate their association with the cytoskeleton (8). The level of PIP 2 decreases upon detachment of cells from the substratum and increases upon reattachment to fibronectin (1). The difference in the levels of PIP 2 is probably due to different rates of phosphorylation of phosphatidyl 4-phosphate to PIP 2 by phosphatidylinositol 4-phosphate 5-kinase. Phosphatidylinositol 4-phosphate 5-kinase is stimulated 3-4-fold by adhesion of cells to fibronectin (1), probably through interactions with the small GTP-binding proteins Rac and Rho, the latter of which has also been implicated in the regulation of assembly of actin stress fibers and focal adhesions (9 -13).PIP 2 may enter several different pathways in signal transduction. It can be hydrolyzed by phospholipase C␥ to generate two intracellular messengers: inositol 1,4,5-triphosphate, which mobilizes Ca 2ϩ , and diacylglycerol, which is a physiological activator of protein kinase C (PKC). It can be further phosphorylated by phosphatidylinositol 3-kinase to generate phosphatidylinositol 3,4,5-triphosphate (PIP 3 ), which has been proposed to regulate numerous activities including cytoskeletal organization (14) and vesicle trafficking (15). PIP 2 c...

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Section: Pip 2 and Ipmentioning

confidence: 99%

Syndecan-4 Proteoglycan Cytoplasmic Domain and Phosphatidylinositol 4,5-Bisphosphate Coordinately Regulate Protein Kinase C Activity

Oh¹,

Woods²,

Lim³

et al. 1998

Journal of Biological Chemistry

177

151

View full text Add to dashboard Cite

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“…PtdIns(4,5)P2 activates PKC in a Ca" -and phospholipiddependent manner, that resembles in part activation by sn-1,2-diacylglycerol (Chauhan and Brockerhof, 1988 ;Chauhan et al, 1989;Lee and Bell, 1991). The ability of PtdIns(4,5)P2 to activate PKC is unlike any other naturally occurring phospholipid.…”

Section: Lipid Activationmentioning

confidence: 99%

“…Since the level of PtdIns(4,5)P2 is decreased in stimulated cells, PtdIns(4,5)P2 activation may have physiological significance. A major point requiring clarification is whether PtdIns(4,5)P2 inhibits the binding of [3H]phorbol 12,13-dibutyrate ([3H]PDBt) (Chauhan et al, 1989) or interacts at a distinct site (Lee and Bell, 1991). Studies indicate that PtdIns(4,5)P2 activates PKC by mechanisms different from that of sn-I ,2-diacylglycerol and interacts at a site distinct from the phorbol ester binding site.…”

Section: Lipid Activationmentioning

confidence: 99%

The protein kinase C family

Azzi

Boscoboinik

Hensey

1992

European Journal of Biochemistry

355

130

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Protein kinase C represents a structurally homologous group of proteins similar in size, structure and mechanism of activation. They can modulate the biological function of proteins in a rapid and reversible manner. Protein kinase C participates in one of the major signal transduction systems triggered by the external stimulation of cells by various ligands including hormones, neurotransmitters and growth factors. Hydrolysis of membrane inositol phospholipids by phospholipase C or of phosphatidylcholine, generates sn-l,2-diacylglycerol, considered the physiological activator of this kinase. Other agents, such as arachidonic acid, participate in the activation of some of these proteins. Activation of protein kinase C by phorbol esters and related compounds is not physiological and may be responsible, at least in part, for their tumor-promoting activity. The cellular localization of the different calcium-activated protein kinases, their substrate and activator specificity are dissimilar and thus their role in signal transduction is unlike. A better understanding of the exact cellular function of the different protein kinase C isoenzymes requires the identification and characterization of their physiological substrates.The eukaryotic cell is a highly regulated entity, responding to its immediate intracellular environment as well as to external stimuli. Most regulations are mediated, either directly or indirectly, by conformational changes in proteins, and the equilibrium between active and inactive conformational states can be altered by both allosteric and covalent mechanisms. A most common covalent means of regulating protein activity is protein phosphorylation, which is particularly prominent for the role that it serves in signal transduction and is important in many other cellular responses (Edelman et al., 1987). Signals impinging on cells have their effects amplified and distributed by a network of protein phosphorylation and dephosphorylation reactions.

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“…Thus, vesicular localization of a-CKI may be regulated by PIP2, as previously shown for CKI in situ (2,3). Regulation of proteins that associate with membranes may prove to be a general regulatory mechanism, since a number of proteins and enzymes, including tyrosine phosphatases, actin-binding proteins, protein 4.1, and protein kinase C, may also be regulated by PIP2 (13)(14)(15)(16)(17)(18)(19)(20)(21).…”

Section: -L-t-g-t-a-r-y-a S-i-n-a-h-l-g-i-e-q-s-r-r-d-d-m Smentioning

confidence: 99%

“…Pooling of PIP2 may be a result of associations with membrane proteins or with membrane skeletal proteins (13)(14)(15)(16)(17). An increase in membrane PIP2 may saturate the sequestered PIP2 pool, increasing the "free" PIP2, which then modulates a number of enzymes, including the 34-kDa CKI activity (18)(19)(20)(21). Such a mechanism could regulate both CKI activity and association with membranes but would require only a small change in total membrane PIP2 content.…”

mentioning

confidence: 99%

Cell cycle-dependent localization of casein kinase I to mitotic spindles.

Brockman

Größ

Sussman

et al. 1992

Proc. Natl. Acad. Sci. U.S.A.

115

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Casein kinase I (CKI) is a class of protein kinases ubiquitous to all eukaryotic cells. Recently, cDNA clones encoding several bovine CKI isoforms have been sequenced that show high sequence identity to the 1IRR25 gene product of the budding yeast Saccharomyces cerevisiae; MRRM is required for normal cellular growth, nuclear segreption, DNA repair, and melosis. We have raised polyclonal antibodies to a human erythroid 34-kDa CMI and have sequenced a portion of this kinase. The amino acid sequence identifies the CKI as the a-CKI isoform, which is 62% identical to the HRR25 protein kinase. By use of immunofluorescence, the a-CKI has been localized to vesicular cytolic structures and to the centrosome in interphase cells. As cels progress into mitosis, centrospheric stining increases and, in mitosis, a-CKI associates with kinetochore fibers. This lo tion suggests that a-CKI, like HRR25, plays a role in the segregation of chromosomes during mitosis and may be cell cycleregulated both in humans and in yeast.Casein kinase I (CKI) activity is ubiquitous in eukaryotes from human to yeast (1). CKI is an unusual protein kinase in that it has been isolated in active form from the cytosol, membranes, and nuclei (1-3). Generally, CKI from the cytosol or membranes of mammalian cells has an apparent molecular mass of 30-37 kDa (1-3). When CKI has been purified from nuclei, a larger range has been reported, 25-55 kDa (1). Indeed, a 46-kDa casein kinase from yeast is conserved in vertebrates and is located in the nucleus in mouse cells (4). CKI from human erythrocytes is a monomer when purified and has a molecular size of 34-36 kDa, depending upon the phosphorylation state of the enzyme (1, 2, 5).CKI phosphorylates the cytoskeletal proteins myosin, ankyrin, troponin, spectrin, and protein 4.1; neural filaments; neural cellular adhesion molecules; RNA polymerases I and II; translation initiation factors 4B, 4E, and 5; tRNA synthetases; simian virus 40 large T antigen; the insulin receptor; the regulatory subunit (phosphatase inhibitor 2) of protein phosphatase 1; the erythrocyte anion transporter; and metabolic enzymes, including glycogen synthase (reviewed in ref. 1). Some of these substrates undergo defined functional changes when phosphorylated by CKI. For example, in vivo, protein phosphatase 1 (phosphatase inhibitor 2) appears to be phosphorylated by CKI and this inhibits the phosphatase activity (6).Glycogen synthase, when phosphorylated by cAMPdependent protein kinase and then by CKI, is potently inhibited (7). This suggests that CKI phosphorylates substrates synergistically with other protein kinases. In other words, there is a sequence or hierarchy of phosphorylation. Indeed, (2,3). In erythrocytes, the assembly of CKI onto membranes is regulated by PIP2. The protein kinase activity is also inhibited by PIP2, and this occurs over a small change in the total PIP2 content in the membranes (3). This unusual pattern of inhibition may occur as a result of the sequestration of membrane PIP2 into "pools" and may prov...

show abstract

Phosphatidylinositol 4,5-bisphosphate competitively inhibits phorbol ester binding to protein kinase C

Cited by 40 publications

References 59 publications

Syndecan-4 Proteoglycan Cytoplasmic Domain and Phosphatidylinositol 4,5-Bisphosphate Coordinately Regulate Protein Kinase C Activity

Syndecan-4 Proteoglycan Cytoplasmic Domain and Phosphatidylinositol 4,5-Bisphosphate Coordinately Regulate Protein Kinase C Activity

The protein kinase C family

Cell cycle-dependent localization of casein kinase I to mitotic spindles.

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