Muscle-Specific Calpain, p94, Interacts with the Extreme C-Terminal Region of Connectin, a Unique Region Flanked by Two Immunoglobulin C2 Motifs

Kinbara, Kayoko; Sorimachi, Hiroyuki; Ishiura, Shoichi; Suzuki, Koichi

doi:10.1006/abbi.1997.0108

Cited by 106 publications

(75 citation statements)

References 25 publications

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“…The observed link between titin proteolysis and calpain activation in doxorubicin-treated myocytes is similar to earlier work showing the extreme susceptibility of titin to degradation in the presence of calcium and the association of calpain-III (p94) with titin in skeletal muscle (13,24,25). As calpain-III is not expressed in the heart, presumably other members of the calpain family, notably the ubiquitous calpains-I and -II, are responsible for cardiac titin proteolysis (55).…”

Section: Discussionsupporting

confidence: 88%

Anthracyclines Induce Calpain-dependent Titin Proteolysis and Necrosis in Cardiomyocytes

Lim

Zuppinger

Guo

et al. 2004

Journal of Biological Chemistry

261

197

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Titin, the largest myofilament protein, serves as a template for sarcomere assembly and acts as a molecular spring to contribute to diastolic function. Titin is known to be extremely susceptible to calcium-dependent protease degradation in vitro. We hypothesized that titin degradation is an early event in doxorubicin-induced cardiac injury and that titin degradation occurs by activation of the calcium-dependent proteases, the calpains. Treatment of cultured adult rat cardiomyocytes with 1 or 3 mol/liter doxorubicin for 24 h resulted in degradation of titin in myocyte lysates, which was confirmed by a reduction in immunostaining of an antibody to the spring-like (PEVK) domain of titin at the I-band of the sarcomere. The elastic domain of titin appears to be most susceptible to proteolysis because co-immunostaining with an antibody to titin at the M-line was preserved, suggesting targeted proteolysis of the springlike domain of titin. Doxorubicin treatment for 1 h resulted in ϳ3-fold increase in calpain activity, which remained elevated at 48 h. Co-treatment with calpain inhibitors resulted in preservation of titin, reduction in myofibrillar disarray, and attenuation of cardiomyocyte necrosis but not apoptosis. Co-treatment with a caspase inhibitor did not prevent the degradation of titin, which precludes caspase-3 as an early mechanism of titin proteolysis. We conclude that calpain activation is an early event after doxorubicin treatment in cardiomyocytes and appears to target the degradation of titin. Proteolysis of the spring-like domain of titin may predispose cardiomyocytes to diastolic dysfunction, myofilament instability, and cell death by necrosis.

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Section: Discussionsupporting

confidence: 88%

Anthracyclines Induce Calpain-dependent Titin Proteolysis and Necrosis in Cardiomyocytes

Lim

Zuppinger

Guo

et al. 2004

Journal of Biological Chemistry

261

197

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“…The muscle-specific protein calpain3 (p94) is a titin interacting protein that shows a localisation pattern similar to DRAL/FHL-2. It binds to titin in the I-band region and in the M-band domain is-7 (Kinbara et al, 1997). Expression of this protein seems to be specific for skeletal muscle, since no calpain3 protein could be detected in heart (Fougerousse et al, 2000).…”

Section: Discussionmentioning

confidence: 99%

Subcellular targeting of metabolic enzymes to titin in heart muscle may be mediated by DRAL/FHL-2

Lange

Auerbach

McLoughlin

et al. 2002

Journal of Cell Science

235

243

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During sarcomere contraction skeletal and cardiac muscle cells consume large amounts of energy. To satisfy this demand, metabolic enzymes are associated with distinct regions of the sarcomeres in the I-band and in the M-band, where they help to maintain high local concentrations of ATP. To date,the mechanism by which metabolic enzymes are coupled to the sarcomere has not been elucidated. Here, we show that the four and a half LIM-only protein DRAL/FHL-2 mediates targeting of the metabolic enzymes creatine kinase,adenylate kinase and phosphofructokinase by interaction with the elastic filament protein titin in cardiomyocytes. Using yeast two-hybrid assays,colocalisation experiments, co-immunoprecipitation and protein pull-down assays, we show that DRAL/FHL-2 is bound to two distinct sites on titin. One binding site is situated in the N2B region, a cardiac-specific insertion in the I-band part of titin, and the other is located in the is2 region of M-band titin. We also show that DRAL/FHL-2 binds to the metabolic enzymes creatine kinase, adenylate kinase and phosphofructokinase and might target these enzymes to the N2B and is2 regions in titin. We propose that DRAL/FHL-2 acts as a specific adaptor protein to couple metabolic enzymes to sites of high energy consumption in the cardiac sarcomere.

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“…Whether these activities require titin kinase activity or solely its scaffolding role remains to be clarified (Bogomolovas et al, 2014;Lange et al, 2005b). Titin interacts additionally with the cysteine protease calpain-3 in the differentially spliced insertion between domains M9 and M10 (Kinbara et al, 1997); this interaction seems to be dynamically modulated by mechanical forces (Ojima et al, 2010). Interestingly, calpain-3 interacts in turn with myospryn, linking the activity of the two pathways in protein degradation (Sarparanta et al, 2010); the generation of C-terminal titin fragments by calpain might be the prelude to their ubiquitin-dependent degradation, a process that is disrupted in several hereditary titinopathies (Charton et al, 2015;Sarparanta et al, 2010).…”

Section: M-band Cytoskeleton: All's Well That Ends Wellmentioning

confidence: 99%

The sarcomeric cytoskeleton: from molecules to motion

Gautel

Djinović-Carugo

2016

Journal of Experimental Biology

190

177

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Highly ordered organisation of striated muscle is the prerequisite for the fast and unidirectional development of force and motion during heart and skeletal muscle contraction. A group of proteins, summarised as the sarcomeric cytoskeleton, is essential for the ordered assembly of actin and myosin filaments into sarcomeres, by combining architectural, mechanical and signalling functions. This review discusses recent cell biological, biophysical and structural insight into the regulated assembly of sarcomeric cytoskeleton proteins and their roles in dissipating mechanical forces in order to maintain sarcomere integrity during passive extension and active contraction. α-Actinin crosslinks in the Z-disk show a pivot-and-rod structure that anchors both titin and actin filaments. In contrast, the myosin crosslinks formed by myomesin in the M-band are of a balland-spring type and may be crucial in providing stable yet elastic connections during active contractions, especially eccentric exercise.

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Muscle-Specific Calpain, p94, Interacts with the Extreme C-Terminal Region of Connectin, a Unique Region Flanked by Two Immunoglobulin C2 Motifs

Cited by 106 publications

References 25 publications

Anthracyclines Induce Calpain-dependent Titin Proteolysis and Necrosis in Cardiomyocytes

Anthracyclines Induce Calpain-dependent Titin Proteolysis and Necrosis in Cardiomyocytes

Subcellular targeting of metabolic enzymes to titin in heart muscle may be mediated by DRAL/FHL-2

The sarcomeric cytoskeleton: from molecules to motion

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