Mobasheri Ali, Trujillo Elisa, Arteaga Mari-Francis, Martín-Vasallo Pablo
Musculoskeletal Research Group, School of Veterinary Medicine and Science, Faculty of Medicine and Health Sciences, The University of Nottingham, Sutton Bonington LE12 5RD, UK.
Rheumatology Service, University Hospital of the Canary Islands, Tenerife 38320, Spain.
Int J Mol Sci. 2012;13(4):5019-5034. doi: 10.3390/ijms13045019. Epub 2012 Apr 20.
Membrane transport systems participate in fundamental activities such as cell cycle control, proliferation, survival, volume regulation, pH maintenance and regulation of extracellular matrix synthesis. Multiple isoforms of Na(+), K(+)-ATPase are expressed in primary chondrocytes. Some of these isoforms have previously been reported to be expressed exclusively in electrically excitable cells (i.e., cardiomyocytes and neurons). Studying the distribution of Na(+), K(+)-ATPase isoforms in chondrocytes makes it possible to document the diversity of isozyme pairing and to clarify issues concerning Na(+), K(+)-ATPase isoform abundance and the physiological relevance of their expression. In this study, we investigated the expression of Na(+), K(+)-ATPase in a human chondrocyte cell line (C-20/A4) using a combination of immunological and biochemical techniques. A panel of well-characterized antibodies revealed abundant expression of the α1, β1 and β2 isoforms. Western blot analysis of plasma membranes confirmed the above findings. Na(+), K(+)-ATPase consists of multiple isozyme variants that endow chondrocytes with additional homeostatic control capabilities. In terms of Na(+), K(+)-ATPase expression, the C-20/A4 cell line is phenotypically similar to primary and in situ chondrocytes. However, unlike freshly isolated chondrocytes, C-20/A4 cells are an easily accessible and convenient in vitro model for the study of Na(+), K(+)-ATPase expression and regulation in chondrocytes.
膜转运系统参与细胞周期调控、增殖、存活、体积调节、pH维持以及细胞外基质合成调节等基本活动。原发性软骨细胞中表达多种Na(+)、K(+)-ATP酶同工型。此前有报道称，其中一些同工型仅在电兴奋性细胞（即心肌细胞和神经元）中表达。研究软骨细胞中Na(+)、K(+)-ATP酶同工型的分布，有助于记录同工酶配对的多样性，并阐明有关Na(+)、K(+)-ATP酶同工型丰度及其表达的生理相关性的问题。在本研究中，我们结合免疫和生化技术，研究了人软骨细胞系（C-20/A4）中Na(+)、K(+)-ATP酶的表达。一组特性明确的抗体显示α1、β1和β2同工型表达丰富。质膜的蛋白质印迹分析证实了上述发现。Na(+)、K(+)-ATP酶由多种同工酶变体组成，赋予软骨细胞额外的稳态控制能力。就Na(+)、K(+)-ATP酶表达而言，C-20/A4细胞系在表型上与原发性和原位软骨细胞相似。然而，与新鲜分离的软骨细胞不同，C-20/A4细胞是一种易于获取且方便的体外模型，用于研究软骨细胞中Na(+)、K(+)-ATP酶的表达和调节。
