Dissociation of phorbol esters leads to immediate redistribution to the cytosol of protein kinases C alpha and C delta in mouse keratinocytes.

Szállási, Zoltán; Smith, Colin B.; Blumberg, Peter M.

doi:10.1016/s0021-9258(18)46960-8

Cited by 34 publications

(8 citation statements)

References 19 publications

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“…An in vitro study has indicated that PKCI3 and ~/may also be capable of interacting with actin, in a PS-dependent manner (Zalewski et al, 1991). However, many PKC isoforms that interact with lipid vesicles and purified proteins in in vitro systems do not associate with these receptors in the intact cell (Szallasi et al, 1994). Our assays of PKC binding have demonstrated that PKCe was the only endogenous isoform of PKC that directly interacted with purified actin in the absence of PS.…”

Section: Discussionmentioning

confidence: 87%

Identification and localization of an actin-binding motif that is unique to the epsilon isoform of protein kinase C and participates in the regulation of synaptic function.

Prekeris

Mayhew

Cooper

et al. 1996

The Journal of Cell Biology

238

188

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Abstract. Individual isoforms of the protein kinase C (PKC) family of kinases may have assumed distinct responsibilities for the control of complex and diverse cellular functions. In this study, we show that an isoform specific interaction between PKCe and filamentous actin may serve as a necessary prelude to the enhancement of glutamate exocytosis from nerve terminals. Using a combination of cosedimentation, overlay, and direct binding assays, we demonstrate that filamentous actin is a principal anchoring protein for PKCe within intact nerve endings. The unusual stability and direct nature of this physical interaction indicate that actin filaments represent a new class of PKC-binding protein. The binding of PKCe to actin required that the kinase be activated, presumably to expose a cryptic binding site that we have identified and shown to be located between the first and second cysteine-rich regions within the regulatory domain of only this individual isoform of PKC. Arachidonic acid (AA) synergistically interacted with diacylglycerol to stimulate actin binding to PKCe. Once established, this protein-protein interaction securely anchored PKCe to the cytoskeletal matrix while also serving as a chaperone that maintained the kinase in a catalytically active conformation. Thus, actin appears to be a bifunctional anchoring protein that is specific for the PKCe isoform. The assembly of this isoform-specific signaling complex appears to play a primary role in the PKC-dependent facilitation of glutamate exocytosis.VOLUTION has conserved a fundamental mechanism that ensures the sorting and fusion of secretory vesicles upon their delivery to appropriate destinations along the secretory pathway. In many eukaryotes, however, alternative pathways have emerged in which vesicle delivery and fusion have become rigorously regulated events that are capable of manifesting use-dependent variations in the probability of their occurrence. Glutamate exocytosis is a particularly striking example of a secretory event that, in presynaptic nerve terminals, has acquired a highly evolved mechanism for regulating the efficiency of excitatory synaptic transmission. Moreover, it has been established that use-dependent changes in the reliability (Stevens and Wang, 1994) and extent (Schulz et al., 1994) of glutamate exocytosis directly participate in certain forms of synaptic plasticity.Studies from many laboratories suggest that a conditional relationship may exist between the efficiency of glutamate release and the activity of presynaptic protein

show abstract

Section: Discussionmentioning

confidence: 87%

Identification and localization of an actin-binding motif that is unique to the epsilon isoform of protein kinase C and participates in the regulation of synaptic function.

Prekeris

Mayhew

Cooper

et al. 1996

The Journal of Cell Biology

238

188

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“…Membrane-associated PKCg could have been redistributed back to the cytosol by the 24-h postconditioning time point. Moreover, the suggestion that prolonged translocation of PKC from the soluble to an integral membrane protein form plays an important role in memory processes (Alkon and Rasmussen, 1988;Burgoyne, 1989) has been questioned, based on the observation of rapid redistribution of membrane- associated PKC to the cytosol after the dissociation of applied phorbol esters in vivo (Szallasi et al, 1994;Mosior and Newton, 1995).…”

mentioning

confidence: 99%

?isoform-selective changes in PKC immunoreactivity after trace eyeblink conditioning in the rabbit hippocampus

Zee¹,

Kronforst-Collins²,

Maizels³

et al. 1997

Hippocampus

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An immunocytochemical examination of the rabbit hippocampus was done to determine which of the Ca 21 -dependent protein kinase C (PKC) isoforms (PKCa, -bI, -bII, or -g) are involved in associative learning. The hippocampally dependent trace eyeblink conditioning task was used for behavioral training, and pseudoconditioned and naive animals served as controls. Significant increases (P F 0.05) in staining intensity were found with antibodies reactive with the catalytic or the regulatory domain of PKCg in conditioned animals compared with naive and pseudoconditioned subjects at a 24-h post-conditioning time point. The increase was found in CA1 and CA3 pyramidal cell bodies, in apical dendrites and the proximal part of the basilar dendrites, and in cell bodies of dentate granule cells. In contrast, no conditioning-specific changes were found for PKCa, -bI, or -bII in hippocampal neurons. The increase in PKCg immunoreactivity (ir) was significantly less (P F 0.05) in poor learners than in good learners. The correlation between the degree of PKCg-ir and the total number of conditioned responses across training sessions was both positive and significant. These results suggest that PKCg is the major Ca 21 -dependent PKC isoform involved in hippocampal neurons during acquisition of associative memories. Immunoblots revealed no conditioning-induced increase in the total amount or translocation of PKCg at the 24-h time point, and no proteolytic PKC fragments were observed. In agreement with the Western blot data, PKC activity did not differ among naive, pseudoconditioned, and trace conditioned animals. The conditioning-induced increase in antibody binding to the g-isoform must therefore be due to an increased access to the antigenic site(s) as a result of alteration in the tertiary structure of PKCg or in quaternary interactions of PKCg in situ.

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“…For example, the increased membrane association induced by phorbol esters has been proposed to arise from conversion of the enzyme into an integral protein (Kraft & Anderson, 1983;Kazanietz et al, 1992), membrane insertion , transformation from "loose" to "tight" binding (Wolf et al, 1985b) or to be mediated by Ca 2+ bridging (Bell, 1986). The nature of the membrane interaction was recently established in two studies that showed that protein kinase C's interaction with phorbol estercontaining membranes is reversible both in cells (Szallasi et al, 1994) and in lipid bilayers (Mosior & Newton, 1995) and that binding is driven by interactions primarily at the membrane interface (Mosior & Newton, 1995). However, the role of Ca 2+ in the protein kinase C/phorbol ester interaction is unclear.…”

mentioning

confidence: 99%

Calcium-Independent Binding to Interfacial Phorbol Esters Causes Protein Kinase C To Associate with Membranes in the Absence of Acidic Lipids

Mosior

Newton

1996

Biochemistry

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The mechanism of interaction of phorbol esters with conventional protein kinase Cs was addressed by examining the direct binding of this class of activators to protein kinase C beta II. Binding measurements reveal that the major role of phorbol esters is to increase the affinity of protein kinase C for membranes by several orders of magnitude. The relative increase depends linearly on the mole fraction of phorbol esters in membranes, with the potency illustrated by the finding that 1 mol% phorbol 12-myristate 13-acetate (PMA) increases protein kinase C's membrane association by approximately 4 orders of magnitude. For comparison, diacylglycerol (DG), which also activates protein kinase C by increasing the enzyme's membrane affinity, is 2 orders of magnitude less effective than PMA in altering protein kinase C's membrane affinity. The remarkably high-affinity interaction with phorbol esters allowed us to measure the direct binding of protein kinase C to PMA in neutral membranes and, thus, to evaluate the effect of Ca2+ on the phorbol ester interaction in the absence of Ca2+ effects on the enzyme's interaction with acidic lipids. Changing the Ca2+ concentration over 5 orders of magnitude had no effect on the direct interaction of protein kinase C with PMA immobilized in phosphatidylcholine membranes. Thus, the Ca(2+)-binding site for membrane association and the phorbol ester-binding site do not interact allosterically. Lastly, a method that does not have the limitations of the Scatchard plot for analysis of amphitropic proteins was used to determine the dissociation constant of protein kinase C from phorbol esters: expressed relative to membrane lipids, the dissociation constant is 1.5 x 10(-5) mol %. In summary, our data reveal that (1) the direct binding of protein kinase C to phorbol esters, in the absence of interactions with acidic lipids, provides a major contribution to the free energy change involved in the association of protein kinase C with membranes and (2) this interaction is not regulated by Ca2+.

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Dissociation of phorbol esters leads to immediate redistribution to the cytosol of protein kinases C alpha and C delta in mouse keratinocytes.

Cited by 34 publications

References 19 publications

Identification and localization of an actin-binding motif that is unique to the epsilon isoform of protein kinase C and participates in the regulation of synaptic function.

Identification and localization of an actin-binding motif that is unique to the epsilon isoform of protein kinase C and participates in the regulation of synaptic function.

?isoform-selective changes in PKC immunoreactivity after trace eyeblink conditioning in the rabbit hippocampus

Calcium-Independent Binding to Interfacial Phorbol Esters Causes Protein Kinase C To Associate with Membranes in the Absence of Acidic Lipids

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