Degradation of sarcomeric and cytoskeletal proteins in cultured skeletal muscle cells

Purintrapiban, Juntipa

doi:10.1016/j.cbpc.2003.06.001

Cited by 15 publications

(21 citation statements)

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“…We chose to analyze the depletion patterns of the calpain substrate desmin because desmin is a structural cytoskeletal protein responsible for maintaining sarcomeric alignment in intact muscle. As well, previous work in cultured cells supports desmin depletion during conditions of protein degradation (Purintrapiban et al 2003). Although the amount of desmin depletion observed with HU did not reach statistical signiWcance, there was nevertheless a tendency towards desmin depletion during the earlier stages of HU (i.e.…”

Section: Discussionmentioning

confidence: 56%

Calpain/calpastatin activities and substrate depletion patterns during hindlimb unweighting and reweighting in skeletal muscle

et al. 2007

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Unloading of skeletal muscle by hindlimb unweighting (HU) is characterized by atrophy, protein loss, and an elevation in intracellular Ca(2+) levels that may be sufficient to activate Ca(2+)-dependent proteases (calpains). In this study, we investigated the time course of calpain activation and the depletion pattern of a specific structural protein (desmin) with unloading and subsequent reweighting. Rats underwent 12 h, 24 h, 72 h or 9 days of HU, followed by reweighting for either 0, 12 or 24 h. Total calpain-like activity was elevated with HU in skeletal muscle (P < 0.05) and was further enhanced with reweighting (P < 0.05). The increases in calpain-like activity were associated with a proportional increase in activity of the particulate fraction (P < 0.05). Activity of the mu-calpain isoform was elevated with 12 and 24 h of HU (P < 0.05) and returned to control levels thereafter. With reweighting, activities of mu-calpain were elevated above control levels for all HU groups except 9 days (P < 0.05). In contrast, minimal changes in m-calpain and calpastatin activity were observed with HU and reweighting. Although desmin depletion levels did not reach statistical significance, a significant inverse relationship was found between the mu-calpain/calpastatin ratio and the amount of desmin in isolated myofibrils (R = -0.83, P < 0.001). The results suggest that calpain activation is an early event during unloading in skeletal muscle, and that the majority of the increase in calpain activity can be attributed to the micro-isoform.

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Section: Discussionmentioning

confidence: 56%

Calpain/calpastatin activities and substrate depletion patterns during hindlimb unweighting and reweighting in skeletal muscle

et al. 2007

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“…calpain), and the proteasome system. Although lysosomal proteases are activated in skeletal muscle undergoing disuse atrophy, the importance of these proteases appears limited (12,20,47). In contrast, strong evidence indicates that both calpain and the proteasome system play important roles in muscle protein breakdown during muscle atrophy (12,24,47).…”

Section: Proteolytic Pathways In Skeletal Musclementioning

confidence: 90%

“…Calpains (calpain I and II) are Ca 2ϩ -dependent cysteine proteases that are activated in skeletal muscle during periods of inactivity (14). Although calpains do not directly degrade the contractile proteins actin and myosin, calpain releases sarcomeric proteins by cleaving cytoskeletal proteins (e.g., titin, nebulin) that anchor the contractile elements (31,47) (Fig. 1).…”

Section: Proteolytic Pathways In Skeletal Musclementioning

confidence: 98%

Mechanisms of disuse muscle atrophy: role of oxidative stress

Powers

Kavazis

DeRuisseau

2005

American Journal of Physiology-Regulatory, Integrative and Comp

316

278

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Prolonged periods of skeletal muscle inactivity lead to a loss of muscle protein and strength. Advances in cell biology have progressed our understanding of those factors that contribute to muscle atrophy. To this end, abundant evidence implicates oxidative stress as a potential regulator of proteolytic pathways leading to muscle atrophy during periods of prolonged disuse. This review will address the role of reactive oxygen species and oxidative stress as potential contributors to the process of disuse-mediated muscle atrophy. The first section of this article will discuss our current understanding of muscle proteases, sources of reactive oxygen in muscle fibers, and the evidence linking oxidative stress to disuse muscle atrophy. The second section of this review will highlight gaps in our knowledge relative to the specific role of oxidative stress in the regulation of disuse muscle atrophy. By discussing unresolved issues and suggesting topics for future research, it is hoped that this review will serve as a stimulus for the expansion of knowledge in this exciting field.

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“…This signaling orchestrates three known proteolytic systems working together in muscle atrophy, ie, the calcium-dependent calpain system, the lysosomal protease system (cathepsins), and the ubiquitin-proteasome system [21]. The ubiquitous calpains (CAPN1 and CAPN2) are involved in the disassembly of sarcomeric proteins in atrophy models [20,28,41]. Therefore, myofibrillar proteins become available for ubiquitination, a prerequisite for degradation by proteasomes that are not able to degrade intact myofibrils [1].…”

Section: Introductionmentioning

confidence: 98%

Expression of Atrophy mRNA Relates to Tendon Tear Size in Supraspinatus Muscle

Schmutz

Fuchs

Regenfelder

et al. 2009

Clinical Orthopaedics &Amp; Related Research

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Skeletal muscle atrophy and fatty infiltration develop after tendon tearing. The extent of atrophy serves as one prognostic factor for the outcome of surgical repair of rotator cuff tendon tears. We asked whether mRNA of genes involved in regulation of degradative processes leading to muscle atrophy, ie, FOXOs, MSTN, calpains, cathepsins, and transcripts of the ubiquitin-proteasome pathway, are overexpressed in the supraspinatus muscle in patients with and without rotator cuff tears. We evaluated biopsy specimens collected during surgery of 53 consecutive patients with different sizes of rotator cuff tendon tears and six without tears. The levels of corresponding gene transcripts in total RNA extracts were assessed by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Supraspinatus muscle atrophy was assessed by MRI. The area of muscle tissue (or atrophy), decreased (increased) with increasing tendon tear size. The transcripts of CAPN1, UBE2B, and UBE3A were upregulated more than twofold in massive rotator cuff tears as opposed to smaller tears or patients without tears. These atrophy gene products may be involved in cellular processes that impair functional recovery of affected muscles after surgical rotator cuff repair. However, the damaging effects of gene products in their respective proteolytic processes on muscle structures and proteins remains to be investigated.

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Degradation of sarcomeric and cytoskeletal proteins in cultured skeletal muscle cells

Cited by 15 publications

References 0 publications

Calpain/calpastatin activities and substrate depletion patterns during hindlimb unweighting and reweighting in skeletal muscle

Calpain/calpastatin activities and substrate depletion patterns during hindlimb unweighting and reweighting in skeletal muscle

Mechanisms of disuse muscle atrophy: role of oxidative stress

Expression of Atrophy mRNA Relates to Tendon Tear Size in Supraspinatus Muscle

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