Abstract P191: Calpain-Generated Free PKCα Catalytic Domains Induce HDAC5 Nuclear Export and Regulate Cardiac Gene Transcription

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Yan Zhang ◽  
Scot Matkovich ◽  
Abhinav Diwan ◽  
Min-Young Kang ◽  
Gerald W Dorn

Receptor-mediated activation of protein kinase (PK) C is a central pathway regulating cell growth, homeostasis, and programmed death. Recently, we showed that calpain-mediated proteolytic processing of PKC in ischemic myocardium activates PKC signaling in a receptor-independent manner by releasing a persistent and constitutively active free catalytic C-terminal fragment, PKCα-CT. This unregulated kinase provokes cardiomyopathy, but the mechanisms remain unclear. We examined hypothesis that PKCα-CT has transcriptional activity. Using immunoblot analysis and confocal microscopy, we found that PKCα-CT localized in part to nuclei and spontaneously induced cytosolic relocalization HDAC5 of the transcriptional regulator. Co- expression of calpain 1 with full length PKCα can generate PKCα-CT and produced the same HDAC5 cytosolic relocalization, whereas full length PKCα alone had no such effect. HDAC5 cytosolic relocalization induced by PKCα-CT was abolished by the protein kinase inhibitor GO6976, but not by PKD inhibitor CID 755673. The in vivo relevance of these findings was examined in transgenic mice expressing PKCα and PKCα-CT. To assess the consequence on gene expression, we performed global transcriptome profiling by Affymetrix microarrays and mRNA sequencing. The two techniques substantially agreed. Compared to control hearts, 621 mRNAs were regulated at least 1.3 fold in PKCα-CT hearts (P< 0.001), only 59 in full-length PKCα hearts. MEF2-dependent inflammatory pathway genes which are putative HDAC targets were upregulated in PKCα-CT heart: 15 MEF2 target mRNAs were upregulated in PKCα-CT hearts (p<0.001), only one in PKCα hearts. These results reveal that PKCα-CT is a potent regulator of pathological cardiac gene expression by localizing to nuclei and directly promoting nuclei-cytoplasmic shuttling of HDAC5. Receptor-independent effect of PKCα-CT and HDAC phosphorylation in ischemic hearts has broad ramifications for understanding and preventing the pathological transcriptional stress response.

2002 ◽  
Vol 277 (51) ◽  
pp. 49438-49445 ◽  
Author(s):  
Seunghwan Lim ◽  
Yonglong Zou ◽  
Eileen Friedman

Mirk/Dyrk1B protein kinase was shown in an earlier study to function as a transcriptional activator of HNF1α, which Mirk phosphorylates at Ser249within its CREB (cAMP-response element-binding protein)-binding protein (CBP) binding domain (1). The MAPK kinase MKK3 was also shown to activate Mirk as a protein kinase, implicating Mirk in the biological response to certain stress agents. Another MKK3 substrate, p38MAPK, is now shown to inhibit the function of Mirk as a transcriptional activator in a kinase-independent manner. Co-immunoprecipitation experiments demonstrated that kinase-inactive p38AF, as well as wild-type p38, sequestered Mirk and prevented its association with MKK3. Only the p38α and p38β isoforms, but not the γ or δ isoforms, complexed with Mirk. p38αMAPK blocked Mirk activation of HNF1α in a dose-dependent manner, with high levels of kinase-inactive p38αAF completely suppressing the activity of Mirk. Size fractionation by fast protein liquid chromatography on Superdex 200 demonstrated that Mirk is not found as a monomerin vivo, but is found within 150–700 kDa subnuclear complexes, which co-migrate with the nuclear body scaffolding protein PML. Endogenous Mirk, p38, and MKK3 co-migrate within 500–700-kDa protein complexes, which accumulate when nuclear export is blocked by leptomycin B. Stable overexpression of Mirk increases the fraction of Mirk protein and p38 protein within these 500–700 kDa complexes, suggesting that the complexes act as nuclear depots for Mirk and p38. Sequestration of Mirk by p38 may occur within these subnuclear complexes. Synchronization experiments demonstrated that Mirk levels fluctuate about 10-fold within the cell cycle, while p38 levels do not, leading to the speculation that endogenous p38 could only block Mirk function when Mirk levels were low in S phase and not when Mirk levels were elevated in G0/G1. These data suggest a novel cell cycle-dependent function for p38, suppression of the function of Mirk as a transcriptional activator only when cells are proliferating, and thus limiting Mirk function to growth-arrested cells.


2007 ◽  
Vol 74 (3) ◽  
pp. A34-A35
Author(s):  
M SCHLEISS ◽  
M MCVOY ◽  
X CUI ◽  
Y CHOI ◽  
J ANDERSON ◽  
...  

2000 ◽  
Vol 14 (8) ◽  
pp. 1125-1136 ◽  
Author(s):  
Josep M. Colomer ◽  
Anthony R. Means

Abstract Although isoforms of Ca2+/calmodulin-dependent protein kinase II (CaMKII) have been implicated in the regulation of gene expression in cultured cells, this issue has yet to be addressed in vivo. We report that the overexpression of calmodulin in ventricular myocytes of transgenic mice results in an increase in the Ca2+/calmodulin-independent activity of endogenous CaMKII. The calmodulin transgene is regulated by a 500-bp fragment of the atrial natriuretic factor (ANF) gene promoter which, based on cell transfection studies, is itself known to be regulated by CaMKII. The increased autonomous activity of CaMKII maintains the activity of the transgene and establishes a positive feedforward loop, which also extends the temporal expression of the endogenous ANF promoter in ventricular myocytes. Both the increased activity of CaMKII and transcriptional activation of ANF are highly selective responses to the chronic overexpression of calmodulin. These results indicate that CaMKII can regulate gene expression in vivo and suggest that this enzyme may represent the Ca2+-dependent target responsible for reactivation of the ANF gene during ventricular hypertrophy.


2000 ◽  
Vol 349 (2) ◽  
pp. 403-407 ◽  
Author(s):  
Lihua ZHENG ◽  
Long YU ◽  
Qiang TU ◽  
Min ZHANG ◽  
Hua HE ◽  
...  

Two novel members of the human cAMP-dependent protein kinase inhibitor (PKI) gene family, PKIB and PKIG, were cloned. The deduced proteins showed 70% and 90% identity with mouse PKIβ and PKIγ respectively. Both the already identified pseudosubstrate site and leucine-rich nuclear export signal motifs were defined from the 11 PKIs of different species. The PKIB and PKIG genes were mapped respectively to chromosome 6q21-22.1, using a radiation hybrid GB4 panel, and to chromosome 20q13.12-13.13, using a Stanford G3 panel. Northern-blot analysis of three PKI isoforms, including the PKIA identified previously, revealed significant differences in their expression patterns. PKIB had two transcripts of 1.9 kb and 1.4 kb. The former transcript was abundant in both placenta and brain and the latter was expressed most abundantly in placenta, highly in brain, heart, liver, pancreas, moderately in kidney, skeletal muscle and colon, and very little in the other eight tissues tested. PKIG was widely expressed as a 1.5-kb transcript with the highest level in heart, hardly detectable in thymus and peripheral blood leucocytes and was moderately expressed in the other tissues, with slightly different levels. However, PKIA was specifically expressed as two transcripts of 3.3 kb and 1.5 kb in heart and skeletal muscle. The distinct expression patterns of the three PKIs suggest that their roles in various tissues are probably different.


1995 ◽  
Vol 752 (1 Cardiac Growt) ◽  
pp. 370-386 ◽  
Author(s):  
J. L. SAMUEL ◽  
I. DUBUS ◽  
F. FARHADIAN ◽  
F. MAROTTE ◽  
P. OLIVIERO ◽  
...  

Endocrinology ◽  
2003 ◽  
Vol 144 (3) ◽  
pp. 839-849 ◽  
Author(s):  
Buffy S. Ellsworth ◽  
Brett R. White ◽  
Ann T. Burns ◽  
Brian D. Cherrington ◽  
Annette M. Otis ◽  
...  

Reproductive function is dependent on the interaction between GnRH and its cognate receptor found on gonadotrope cells of the anterior pituitary gland. GnRH activation of the GnRH receptor (GnRHR) is a potent stimulus for increased expression of multiple genes including the gene encoding the GnRHR itself. Thus, homologous regulation of the GnRHR is an important mechanism underlying gonadotrope sensitivity to GnRH. Previously, we have found that GnRH induction of GnRHR gene expression in αT3-1 cells is partially mediated by protein kinase C activation of a canonical activator protein-1 (AP-1) element. In contrast, protein kinase A and a cAMP response element-like element have been implicated in mediating the GnRH response of the GnRHR gene using a heterologous cell model (GGH3). Herein we find that selective removal of the canonical AP-1 site leads to a loss of GnRH regulation of the GnRHR promoter in transgenic mice. Thus, an intact AP-1 element is necessary for GnRH responsiveness of the GnRHR gene both in vitro and in vivo. Based on in vitro analyses, GnRH appeared to enhance the interaction of JunD, FosB, and c-Fos at the GnRHR AP-1 element. Although enhanced binding of cFos reflected an increase in gene expression, GnRH appeared to regulate both FosB and JunD at a posttranslational level. Neither overexpression of a constitutively active Raf-kinase nor pharmacological blockade of GnRH-induced ERK activation eliminated the GnRH response of the GnRHR promoter. GnRH responsiveness was, however, lost in αT3-1 cells that stably express a dominant-negative c-Jun N-terminal kinase (JNK) kinase, suggesting a critical role for JNK in mediating GnRH regulation of the GnRHR gene. Consistent with this possibility, we find that the ability of forskolin and membrane-permeable forms of cAMP to inhibit the GnRH response of the GnRHR promoter is associated with a loss of both JNK activation and GnRH-mediated recruitment of the primary AP-1-binding components.


2001 ◽  
Vol 281 (6) ◽  
pp. G1405-G1412 ◽  
Author(s):  
T. Suzuki ◽  
E. Grand ◽  
C. Bowman ◽  
J. L. Merchant ◽  
A. Todisco ◽  
...  

Helicobacter pyloriand proinflammatory cytokines have a direct stimulatory effect on gastrin release from isolated G cells, but little is known about the mechanism by which these factors regulate gastrin gene expression. We explored whether tumor necrosis factor (TNF)-α and interleukin (IL)-1 directly regulate gastrin gene expression and, if so, by what mechanism. TNF-α and IL-1 significantly increased gastrin mRNA in canine G cells to 181 ± 18% and 187 ± 28% of control, respectively, after 24 h of treatment. TNF-α and IL-1 stimulated gastrin promoter activity to a maximal level of 285 ± 12% and 415 ± 26% of control. PD-98059 (a mitogen-activated protein kinase kinase inhibitor), SB-202190 (a p38 kinase inhibitor), and GF-109203 (a protein kinase C inhibitor) inhibited the stimulatory action of both cytokines on the gastrin promoter. In conclusion, both cytokines can directly regulate gastrin gene expression via a mitogen-activated protein kinase- and protein kinase C-dependent mechanism. These data suggest that TNF-α and IL-1 may play a direct role in Helicobacter pylori-induced hypergastrinemia.


F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 1166 ◽  
Author(s):  
Olivia R. Buonarati ◽  
Peter B. Henderson ◽  
Geoffrey G. Murphy ◽  
Mary C. Horne ◽  
Johannes W. Hell

Background: The L-type Ca2+ channel Cav1.2 is a prominent regulator of neuronal excitability, synaptic plasticity, and gene expression. The central element of Cav1.2 is the pore-forming α11.2 subunit. It exists in two major size forms, whose molecular masses have proven difficult to precisely determine. Recent work suggests that α11.2 is proteolytically cleaved between the second and third of its four pore-forming domains (Michailidis et al,. 2014). Methods: To better determine the apparent molecular masses (MR)of the α11.2 size forms, extensive systematic immunoblotting of brain tissue as well as full length and C-terminally truncated α11.2 expressed in HEK293 cells was conducted using six different region–specific antibodies against α11.2. Results: The full length form of α11.2 migrated, as expected, with an apparent MR of ~250 kDa. A shorter form of comparable prevalence with an apparent MR of ~210 kDa could only be detected in immunoblots probed with antibodies recognizing α11.2 at an epitope 400 or more residues upstream of the C-terminus. Conclusions: The main two size forms of α11.2 are the full length form and a shorter form, which lacks ~350 distal C-terminal residues. Midchannel cleavage as suggested by Michailidis et al. (2014) is at best minimal in brain tissue.


Development ◽  
1999 ◽  
Vol 126 (16) ◽  
pp. 3607-3616 ◽  
Author(s):  
Y. Chen ◽  
J.R. Cardinaux ◽  
R.H. Goodman ◽  
S.M. Smolik

Hedgehog (HH) is an important morphogen involved in pattern formation during Drosophila embryogenesis and disc development. cubitus interruptus (ci) encodes a transcription factor responsible for transducing the hh signal in the nucleus and activating hh target gene expression. Previous studies have shown that CI exists in two forms: a 75 kDa proteolytic repressor form and a 155 kDa activator form. The ratio of these forms, which is regulated positively by hh signaling and negatively by PKA activity, determines the on/off status of hh target gene expression. In this paper, we demonstrate that the exogenous expression of CI that is mutant for four consensus PKA sites [CI(m1-4)], causes ectopic expression of wingless (wg) in vivo and a phenotype consistent with wg overexpression. Expression of CI(m1-4), but not CI(wt), can rescue the hh mutant phenotype and restore wg expression in hh mutant embryos. When PKA activity is suppressed by expressing a dominant negative PKA mutant, the exogenous expression of CI(wt) results in overexpression of wg and lethality in embryogenesis, defects that are similar to those caused by the exogenous expression of CI(m1-4). In addition, we demonstrate that, in cell culture, the mutation of any one of the three serine-containing PKA sites abolishes the proteolytic processing of CI. We also show that PKA directly phosphorylates the four consensus phosphorylation sites in vitro. Taken together, our results suggest that positive hh and negative PKA regulation of wg gene expression converge on the regulation of CI phosphorylation.


1999 ◽  
Vol 276 (5) ◽  
pp. R1525-R1533 ◽  
Author(s):  
Xianzhong Meng ◽  
Brian D. Shames ◽  
Edward J. Pulido ◽  
Daniel R. Meldrum ◽  
Lihua Ao ◽  
...  

This study tested the hypothesis that in vivo norepinephrine (NE) treatment induces bimodal cardiac functional protection against ischemia and examined the roles of α1-adrenoceptors, protein kinase C (PKC), and cardiac gene expression in cardiac protection. Rats were treated with NE (25 μg/kg iv). Cardiac functional resistance to ischemia-reperfusion (25/40 min) injury was examined 30 min and 1, 4, and 24 h after NE treatment with the Langendorff technique, and effects of α1-adrenoceptor antagonism and PKC inhibition on the protection were determined. Northern analysis was performed to examine cardiac expression of mRNAs encoding α-actin and myosin heavy chain (MHC) isoforms. Immunofluorescent staining was performed to localize PKC-βI in the ventricular myocardium. NE treatment improved postischemic functional recovery at 30 min, 4 h, and 24 h but not at 1 h. Pretreatment with prazosin or chelerythrine abolished both the early adaptive response at 30 min and the delayed adaptive response at 24 h. NE treatment induced intranuclear translocation of PKC-βI in cardiac myocytes at 10 min and increased skeletal α-actin and β-MHC mRNAs in the myocardium at 4–24 h. These results demonstrate that in vivo NE treatment induces bimodal myocardial functional adaptation to ischemia in a rat model. α1-Adrenoceptors and PKC appear to be involved in signal transduction for inducing both the early and delayed adaptive responses. The delayed adaptive response is associated with the expression of cardiac genes encoding fetal contractile proteins, and PKC-βI may transduce the signal for reprogramming of cardiac gene expression.


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