Functional Proteomics Laboratory, Regional Centre for Biotechnology (RCB), NCR Biotech Science Cluster, Faridabad 121001, India.
School of Biotechnology, Kalinga Institute of Industrial Technology (KIIT), Bhubaneswar, Odisha 751024, India.
Biosci Rep. 2021 Apr 30;41(4). doi: 10.1042/BSR20203690.
Calpain belongs to the calcium-dependent non-lysosomal cysteine protease. Calpain-1 (C1) and calpain-2 (C2) expression are ubiquitous in mammals and an important mediator of the action of calcium. Specific substrate cleavage by C1 and C2 is critical for several calcium-dependent cellular pathways including neuronal function, muscle contraction, signal transduction, cell differentiation, proliferation, and apoptosis. Research suggests that C1 and C2 perform similar functions due to their structurally highly similar isoforms. Increasing evidence suggests that C1 and C2 carry out their specific function in vivo. A recent paper published by Shinkai-Ouchi et al. (Bioscience Reports (2020) 40, DOI: 10.1042/BSR20200552) elucidated the mechanism to differentiate the function of each calpain with respect to the efficiency and longevity for proteolysis after activation. Further, the study represented that C1 and C2 do not synergistically perform their work in vitro. On the other hand, the activity of C1 is reduced in presence of C2. This insight establishes the platform for future studies to examine how C2 regulates the C1 for substrate proteolysis.
钙蛋白酶属于钙依赖性非溶酶体半胱氨酸蛋白酶。钙蛋白酶-1（C1）和钙蛋白酶-2（C2）在哺乳动物中广泛表达，是钙作用的重要介质。C1 和 C2 对特定底物的切割对于几种依赖钙的细胞途径至关重要，包括神经元功能、肌肉收缩、信号转导、细胞分化、增殖和细胞凋亡。研究表明，由于其结构高度相似的同工型，C1 和 C2 发挥相似的功能。越来越多的证据表明，C1 和 C2 在体内执行其特定功能。Shinkai-Ouchi 等人最近发表的一篇论文（Bioscience Reports（2020）40，DOI：10.1042/BSR20200552）阐明了区分每种钙蛋白酶功能的机制，涉及到激活后蛋白水解的效率和寿命。此外，该研究表明 C1 和 C2 在体外不会协同发挥作用。另一方面，C2 的存在会降低 C1 的活性。这一发现为未来的研究奠定了基础，以研究 C2 如何调节 C1 进行底物蛋白水解。
