Translational control of apolipoprotein B mRNA via insulin and the protein kinase C signaling cascades: Evidence for modulation of RNA–protein interactions at the 5′UTR

2007 ◽  
Vol 459 (1) ◽  
pp. 10-19 ◽  
Author(s):  
Konstantinos Gus Sidiropoulos ◽  
Arthur Zastepa ◽  
Khosrow Adeli
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

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.


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.


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.


2010 ◽  
Vol 21 (8) ◽  
pp. 1398-1408 ◽  
Author(s):  
HongBin Wang ◽  
Marcelo G. Kazanietz

The C1 domains in protein kinase C (PKC) isozymes and other signaling molecules are responsible for binding the lipid second messenger diacylglycerol and phorbol esters, and for mediating translocation to membranes. Previous studies revealed that the C1 domain in α- and β-chimaerins, diacylglycerol-regulated Rac-GAPs, interacts with the endoplasmic reticulum/Golgi protein p23/Tmp21. Here, we found that p23/Tmp21 acts as a C1 domain-docking protein that mediates perinuclear translocation of β2-chimaerin. Glu227 and Leu248 in the β2-chimaerin C1 domain are crucial for binding p23/Tmp21 and perinuclear targeting. Interestingly, isolated C1 domains from individual PKC isozymes differentially interact with p23/Tmp21. For PKCε, it interacts with p23/Tmp21 specifically via its C1b domain; however, this association is lost in response to phorbol esters. These results demonstrate that p23/Tmp21 acts as an anchor that distinctively modulates compartmentalization of C1 domain-containing proteins, and it plays an essential role in β2-chimaerin relocalization. Our study also highlights the relevance of C1 domains in protein–protein interactions in addition to their well-established lipid-binding properties.


2005 ◽  
Vol 90 (2) ◽  
pp. 1163-1170 ◽  
Author(s):  
Markus Eszlinger ◽  
Knut Krohn ◽  
Kerstin Berger ◽  
Jürgen Läuter ◽  
Siegfried Kropf ◽  
...  

In contrast to the molecular etiology of autonomously functioning thyroid nodules, the molecular cause of cold thyroid nodules (CTNs), their benign, functional inactive counterparts, are so far largely unknown. Because of the partially dedifferentiated phenotype of CTNs, alterations in signaling cascades that favor proliferation, but not differentiation, are likely candidates for tumor induction and progression. The importance of RAS mutations for the development of benign nodules with follicular histology is still in question. However, differentially expressed genes in the context of their signaling cascades could define aberrant signaling in CTNs. Therefore, we investigated gene expression in 22 CTNs and their normal surrounding tissue using Affymetrix GeneChips. Most prominently, data analysis revealed an increased expression of cell cycle-associated genes and a special relevance of protein kinase C signaling, whereas no evidence of RAS-MAPK signaling in CTNs was found. Moreover, we determined 31 differentially regulated genes in CTNs, including several histone mRNAs. Taken together, these results explain recent findings showing an increased proliferation in CTNs and draw attention to protein kinase C signaling, but away from RAS-MAPK signaling, as being involved in the etiology of CTNs.


1996 ◽  
Vol 24 (4) ◽  
pp. 581S-581S
Author(s):  
John A. Watson ◽  
Paul Littlebury ◽  
Nigel Groome ◽  
Martin G. Rumsby

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