Protein kinase C-δ C2-like domain is a binding site for actin and enables actin redistribution in neutrophils

2001 ◽  
Vol 357 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Guillermo LÓPEZ-LLUCH ◽  
Margaret M. BIRD ◽  
Benito CANAS ◽  
Jasminka GODOVAC-ZIMMERMAN ◽  
Anne RIDLEY ◽  
...  

Neutrophils play a key role in host-defence mechanisms against invading pathogens, using their capacity to migrate, engulf micro-organisms and produce toxic radicals. Protein kinase C (PKC) isotypes are important intracellular regulators of these processes in neutrophils. PKC isotypes themselves are controlled by interactions with lipids, Ca2+ and proteins. The C2-like domain of PKC-δ (δC2) has been identified as a protein-interaction domain in this PKC isotype. In the present paper we have investigated the contribution of protein interactions at this domain to the regulation/function of PKC-δ in neutrophils. Using affinity chromatography we identified actin as a δC2 binding partner in these cells. Fluorescein-labelled δC2, microinjected into immobilized neutrophils, interacts with filamentous actin (F-actin) inside the cell. PKC-δ co-localizes with F-actin in neutrophils, in lamellipodia at the leading edge of the cell. Stimulation with phorbol ester or IgG-opsonized Staphylococcus aureus results in co-ordinated redistribution of PKC-δ and F-actin, and a PKC-δ inhibitor inhibits these changes. Microinjection of δC2 also inhibits F-actin redistribution. Thus PKC-δ binds to F-actin through its C2 domain, and these interactions are important in regulating actin redistribution in neutrophils.

2021 ◽  
Author(s):  
Ameya J. Limaye ◽  
George N. Bendzunas ◽  
Eileen Kennedy

Protein Kinase C (PKC) is a member of the AGC subfamily of kinases and regulates a wide array of signaling pathways and physiological processes. Protein-protein interactions involving PKC and its...


2003 ◽  
pp. 389-395
Author(s):  
Peter J. Parker ◽  
Joanne Durgan ◽  
Xavier Iturrioz ◽  
Sipeki Szabolcs

Author(s):  
Simon J Slater ◽  
Brigid A Stagliano ◽  
Jodie L Seiz ◽  
Jeffery P Curry ◽  
Shawn K Milano ◽  
...  

Cancers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 346 ◽  
Author(s):  
Purusottam Mohapatra ◽  
Vikas Yadav ◽  
Maren Toftdahl ◽  
Tommy Andersson

WNT5A is a well-known mediator of melanoma cell invasion and metastasis via its ability to activate protein kinase C (PKC), which is monitored by phosphorylation of the endogenous PKC substrate myristoylated alanine-rich c-kinase substrate (MARCKS). However, a possible direct contribution of MARCKS in WNT5A-mediated melanoma cell invasion has not been investigated. Analyses of melanoma patient databases suggested that similar to WNT5A expression, MARCKS expression appears to be associated with increased metastasis. A relationship between the two is suggested by the findings that recombinant WNT5A (rWNT5A) induces both increased expression and phosphorylation of MARCKS, whereas WNT5A silencing does the opposite. Moreover, WNT5A-induced invasion of melanoma cells was blocked by siRNA targeting MARCKS, indicating a crucial role of MARCKS expression and/or its phosphorylation. Next, we employed a peptide inhibitor of MARCKS phosphorylation that did not affect MARCKS expression and found that it abolished WNT5A-induced melanoma cell invasion. Similarly, rWNT5A induced the accumulation of phosphorylated MARCKS in membrane protrusions at the leading edge of melanoma cells. Our results demonstrate that WNT5A-induced phosphorylation of MARCKS is not only an indicator of PKC activity but also a crucial regulator of the metastatic behavior of melanoma and therefore an attractive future antimetastatic target in melanoma patients.


2001 ◽  
Vol 280 (3) ◽  
pp. H946-H955 ◽  
Author(s):  
Jason M. Pass ◽  
Yuting Zheng ◽  
William B. Wead ◽  
Jun Zhang ◽  
Richard C. X. Li ◽  
...  

Receptors for activated C kinase (RACKs) have been shown to facilitate activation of protein kinase C (PKC). However, it is unknown whether PKC activation modulates RACK protein expression and PKC-RACK interactions. This issue was studied in two PKCε transgenic lines exhibiting dichotomous cardiac phenotypes: one exhibits increased resistance to myocardial ischemia (cardioprotected phenotype) induced by a modest increase in PKCε activity (228 ± 23% of control), whereas the other exhibits cardiac hypertrophy and failure (hypertrophied phenotype) induced by a marked increase in PKCε activity (452 ± 28% of control). Our data demonstrate that activation of PKC modulates the expression of RACK isotypes and PKC-RACK interactions in a PKCε activity- and dosage-dependent fashion. We found that, in mice displaying the cardioprotected phenotype, activation of PKCε enhanced RACK2 expression (178 ± 13% of control) and particulate PKCε-RACK2 protein-protein interactions (178 ± 18% of control). In contrast, in mice displaying the hypertrophied phenotype, there was not only an increase in RACK2 expression (330 ± 33% of control) and particulate PKCε-RACK2 interactions (154 ± 14% of control) but also in RACK1 protein expression (174 ± 10% of control). Most notably, PKCε-RACK1 interactions were identified in this line. With the use of transgenic mice expressing a dominant negative PKCε, we found that the changes in RACK expression as well as the attending cardiac phenotypes were dependent on PKCε activity. Our observations demonstrate that RACK expression is dynamically regulated by PKCε and suggest that differential patterns of PKCε-RACK interactions may be important determinants of PKCε-dependent cardiac phenotypes.


2012 ◽  
Vol 199 (2) ◽  
pp. 331-345 ◽  
Author(s):  
Shujie Wang ◽  
Takashi Watanabe ◽  
Kenji Matsuzawa ◽  
Akira Katsumi ◽  
Mai Kakeno ◽  
...  

Migrating cells acquire front-rear polarity with a leading edge and a trailing tail for directional movement. The Rac exchange factor Tiam1 participates in polarized cell migration with the PAR complex of PAR3, PAR6, and atypical protein kinase C. However, it remains largely unknown how Tiam1 is regulated and contributes to the establishment of polarity in migrating cells. We show here that Tiam1 interacts directly with talin, which binds and activates integrins to mediate their signaling. Tiam1 accumulated at adhesions in a manner dependent on talin and the PAR complex. The interactions of talin with Tiam1 and the PAR complex were required for adhesion-induced Rac1 activation, cell spreading, and migration toward integrin substrates. Furthermore, Tiam1 acted with talin to regulate adhesion turnover. Thus, we propose that Tiam1, with the PAR complex, binds to integrins through talin and, together with the PAR complex, thereby regulates Rac1 activity and adhesion turnover for polarized migration.


1992 ◽  
Vol 119 (4) ◽  
pp. 797-810 ◽  
Author(s):  
A Rodríguez Del Castillo ◽  
M L Vitale ◽  
J M Trifaró

Nicotinic stimulation and high K(+)-depolarization of chromaffin cells cause disassembly of cortical filamentous actin networks and redistribution of scinderin, a Ca(2+)-dependent actin filament-severing protein. These events which are Ca(2+)-dependent precede exocytosis. Activation of scinderin by Ca2+ may cause disassembly of actin filaments leaving cortical areas of low cytoplasmic viscosity which are the sites of exocytosis (Vitale, M. L., A. Rodríguez Del Castillo, L. Tchakarov, and J.-M. Trifaró. 1991. J. Cell. Biol. 113:1057-1067). It has been suggested that protein kinase C (PKC) regulates secretion. Therefore, the possibility that PKC activation might modulate scinderin redistribution was investigated. Here we report that PMA, a PKC activator, caused scinderin redistribution, although with a slower onset than that induced by nicotine. PMA effects were independent of either extra or intracellular Ca2+ as indicated by measurements of Ca2+ transients, and they were likely to be mediated through direct activation of PKC because inhibitors of the enzyme completely blocked the response to PMA. Scinderin was not phosphorylated by the kinase and further experiments using the Na+/H+ antiport inhibitors and intracellular pH determinations, demonstrated that PKC-mediated scinderin redistribution was a consequence of an increase in intracellular pH. Moreover, it was shown that scinderin binds to phosphatidylserine and phosphatidylinositol 4,5-biphosphate liposomes in a Ca(2+)-dependent manner, an effect which was modulated by the pH. The results suggest that under resting conditions, cortical scinderin is bound to plasma membrane phospholipids. The results also show that during nicotinic receptor stimulation both a rise in intracellular Ca2+ and pH are observed. The rise in intracellular pH might be the result of the translocation and activation of PKC produced by Ca2+ entry. This also would explain why scinderin redistribution induced by nicotine is partially (26-40%) inhibited by inhibitors of either PKC or the Na+/H+ antiport. In view of these findings, a model which can explain how scinderin redistribution and activity may be regulated by pH and Ca2+ in resting and stimulated conditions is proposed.


1999 ◽  
Vol 343 (2) ◽  
pp. 443-452 ◽  
Author(s):  
Maree C. FAUX ◽  
Emily N. ROLLINS ◽  
Amelia S. EDWARDS ◽  
Lorene K. LANGEBERG ◽  
Alexandra C. NEWTON ◽  
...  

The A-kinase-anchoring protein AKAP79 co-ordinates the location of cAMP-dependent protein kinase, phosphatase 2B (PP2B/calcineurin) and protein kinase C (PKC) at postsynaptic sites in neurons. In this report we focus on the mechanism of interaction between AKAP79 and PKC. We show that neither lipid activators nor kinase activation are required for association with AKAP79. The anchoring protein binds and inhibits the conserved catalytic core of PKCβII. AKAP79 also associates with conventional, novel and atypical isoforms of PKC in vitro andin vivo, and immunofluorescence staining of rat hippocampal neurons demonstrates that the murine anchoring-protein homologue AKAP150 is co-distributed with PKCα/β, PKCε or PKCℓ. Binding of the AKAP79(31-52) peptide, which inhibits kinase activity, exposes the pseudosubstrate domain of PKCβII, allowing endoproteinase Arg-C proteolysis in the absence of kinase activators. Reciprocal experiments have identified two arginine residues at positions 39 and 40 that are essential for AKAP79(31-52) peptide inhibition of PKCβII. Likewise, the same mutations in the full-length anchoring protein reduced inhibition of PKCβII. Thus AKAP79 associates with multiple PKC isoforms through a mechanism involving protein-protein interactions at the catalytic core where binding of the anchoring protein inhibits kinase activity through displacement of the pseudosubstrate.


Sign in / Sign up

Export Citation Format

Share Document