Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.17 (CaMKII)
 4,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A protein of M(r) 59,000 (p59) was recently cloned and identified as a Heat shock protein Binding Immunophilin (p59/HBI). It participates to the heterooligomeric, non-DNA binding form of steroid receptors, in association with the heat shock protein of M(r) 90,000 (hsp90). It binds the immunosuppressants FK506 and rapamycin and possesses three FKBP-12 (FK506 binding protein of M(r) 12,000)--like domains (I to III), plus a tail containing a putative calmodulin binding site (domain IV). Following expression in E. Coli and purification on Glutathione-Sepharose of either the full-length recombinant p59/HBI, or the recombinant FKBP-like domains, we demonstrate by autoradiography of [alpha 32P]-8-azido ATP and of [alpha 32P]-8-azido GTP photoaffinity labeled complexes, that an ATP (GTP) binding site is located in the domain II. This nucleotide binding property is also found with the highly purified rabbit uterus p59/HBI. The latter, but not the recombinant protein, can be phosphorylated in vitro in the presence of Mn++ and/or of Ca++/Calmodulin in an ATP but not GTP dependent manner, suggesting copurification of a CaM kinase II-like enzyme. Thus it appears that p59/HBI is a multifunctional immunophilin which may be at the crossroad of the endocrine and immunological systems.
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PMID:The mammalian heat shock protein binding immunophilin (p59/HBI) is an ATP and GTP binding protein. 837

Several growth factor- and calcium-regulated kinases such as pp90(rsk) or CaM kinase IV can phosphorylate the transcription factor serum response factor (SRF) at serine 103 (Ser-103). However, it is unknown whether stress-regulated kinases can also phosphorylate SRF. We show that treatment of cells with anisomycin, arsenite, sodium fluoride, or tetrafluoroaluminate induces phosphorylation of SRF at Ser-103 in both HeLa and NIH3T3 cells. This phosphorylation is dependent on the kinase p38/SAPK2 and correlates with the activation of MAPKAP kinase 2 (MK2). MK2 phosphorylates SRF in vitro at Ser-103 with similar efficiency as the small heat shock protein Hsp25 and significantly better than CREB. Comparison of wild type murine fibroblasts with those derived from MK2-deficient mice (Mk(-/-)) reveals MK2 as the major SRF kinase induced by arsenite. These results demonstrate that SRF is targeted by several signal transduction pathways within cells and establishes SRF as a nuclear target for MAPKAP kinase 2.
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PMID:MAPKAP kinase 2 phosphorylates serum response factor in vitro and in vivo. 1031 69

Cytosolic Ca2+ transients associated with contraction and relaxation cycles in skeletal muscle are primarily dependent on the kinetics of Ca2+ release and Ca2+ uptake by the sarcoplasmic reticulum (SR). In humans, sarco(endo)plasmic reticulum Ca2+-ATPases (SERCAs) are solely responsible for the removal of Ca2+ from the cytosol following muscle contraction. There are several signalling systems involved in the acute regulation of SERCAs required to achieve a given Ca2+ transient during muscle contraction-relaxation cycles. Cyclic-AMP-dependent protein kinase and Ca2+/calmodulin-dependent protein kinase signalling activate SERCAs through the regulation of the endogenous SERCA-regulatory proteins, phospholamban and sarcolipin, both of which are highly expressed in human skeletal muscle. Recent studies on the regulation of SERCA2b in arterial smooth muscle and work from my laboratory on the interaction between SERCAs and the inducible 70-kDa heat shock protein suggests a novel role for redox signalling in regulating SERCA activity. In the absence of fatigue, activation of these signalling systems in response to repeated muscle activity serves to increase the rate of cytosolic free Ca2+ ([Ca2+]f) decay (i.e., SR Ca2+ uptake) and the speed of muscle relaxation.
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PMID:The decay phase of Ca2+ transients in skeletal muscle: regulation and physiology. 1944 1

Failure of molecular chaperones to direct the correct folding of newly synthesized proteins leads to the accumulation of misfolded proteins in cells. HSPA4 is a member of the heat shock protein 110 family (HSP110) that acts as a nucleotide exchange factor of HSP70 chaperones. We found that the expression of HSPA4 is upregulated in murine hearts subjected to pressure overload and in failing human hearts. To investigate the cardiac function of HSPA4, Hspa4 knockout (KO) mice were generated and exhibited cardiac hypertrophy and fibrosis. Hspa4 KO hearts were characterized by a significant increase in heart weight/body weight ratio, elevated expression of hypertrophic and fibrotic gene markers, and concentric hypertrophy with preserved contractile function. In response to pressure overload, cardiac hypertrophy and remodeling were further aggravated in the Hspa4 KO compared to wild type (WT) mice. Cardiac hypertrophy in Hspa4 KO hearts was associated with enhanced activation of gp130-STAT3, CaMKII, and calcineurin-NFAT signaling. Protein blot and immunofluorescent analyses showed a significant accumulation of polyubiquitinated proteins in cardiac cells of Hspa4 KO mice. These results suggest that the myocardial remodeling of Hspa4 KO mice is due to accumulation of misfolded proteins resulting from impaired chaperone activity. Further analyses revealed a significant increase in cross sectional area of cardiomyocytes, and in expression levels of hypertrophic markers in cultured neonatal Hspa4 KO cardiomyocytes suggesting that the hypertrophy of mutant mice was a result of primary defects in cardiomyocytes. Gene expression profile in hearts of 3.5-week-old mice revealed a differentially expressed gene sets related to ion channels, muscle-specific contractile proteins and stress response. Taken together, our in vivo data demonstrate that Hspa4 gene ablation results in cardiac hypertrophy and fibrosis, possibly, through its role in protein quality control mechanism.
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PMID:Targeted disruption of Hspa4 gene leads to cardiac hypertrophy and fibrosis. 2288 43

Amyotrophic lateral sclerosis is a neurodegenerative disease characterized by a progressive loss of motor neurons. Although the etiology remains unclear, disturbances in Ca2+ homoeostasis and protein folding are essential features of neurodegeneration. The correct folding of proteins is managed by folding proteins, which are regulated by Ca2+ levels. Therefore, Ca(2+)-sensitive folding proteins represent an important link between disturbed Ca2+ handling and protein misfolding in amyotrophic lateral sclerosis. In the first part of this review, we focus on Ca2+ handling in the endoplasmic reticulum and mitochondria in terms of their roles in protein misfolding. In the second part, we draw attention to the main Ca(2+)-sensitive folding proteins that play a role in motor neuron degeneration such as calreticulin and calnexin, which are involved in the folding of glycosylated proteins. In addition, calmodulin and the Ca2+/calmodulin-dependent protein kinase are discussed as one correlation to oxidative stress. The heat shock protein endoplasmin is associated with the anti-apoptotic insulin-like growth factor pathway that is altered in amyotrophic lateral sclerosis. Grp78, which influences Ca2+ homeostasis in the intraluminal endoplasmic reticulum is upregulated in mice models and amyotrophic lateral sclerosis patients and constitutes a core component of the unfolded protein response. Lastly, the protein disulfide isomerase family is responsible for mediating oxidative protein folding in the endoplasmic reticulum.
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PMID:Calcium-dependent protein folding in amyotrophic lateral sclerosis. 2376 68