ABSTRACT Understanding cell Ca2+ signalling requires the knowledge of proteins involved in this process. Among these proteins are Ca2+ATPases that deplete the cytosol of Ca2+ ions. Here, we will particularly focus on one Ca2+ATPase family: the Sarco/Endoplasmic Reticulum Ca2+ATPases (SERCAs) that pump Ca2+ into the endoplasmic reticulum (ER). The SERCA family includes the products of three genes, named SERCA1 (ATP2A1), SERCA2 (ATP2A2), and SERCA3 (ATP2A3). In the present review, we summarize data on various recently identified SERCA2 and SERCA3 gene products. First of all, we show the 3’-ends of the SERCA2 and SERCA3 genes and the corresponding mRNAs, furthermore, the carboxyl termini of the various novel protein isoforms. We present the SERCA2c and 8 species-specific novel SERCA3 splice variants, the recognition of which is partly thanks to our studies performed in human and rat platelets. Next, data on cell and tissue distribution of these SERCA2 and SERCA3 mRNAs and/or proteins are summarized. Then, the biological relevance of the new SERCA3 gene products is assessed by their intrinsic characteristics and effects on cellular Ca2+ homeostasis. Last, recent data concerning the pathophysiological significance of the SERCA3 mRNAs and /or proteins will beare presented. Taken together, these data provide new aspects of investigations to better understand normal and abnormal cell Ca2+ signalling.
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