Protein phosphatase 1, catalytic subunit, alpha isoform Adenovirus (Ad-PP-1A)

Calmodulin-dependent protein phosphatase, calcineurin, is involved in a wide range of biologic activities, acting as a Ca (2+) -dependent modifier of phosphorylation status. In testis, the motility of the sperm is thought to be controlled by cAMP-dependent phosphorylation and a unique form of calcineurin appears to be associated with the flagellum. The calcineurin holoenzyme is composed of catalytic and regulatory subunits of 60 and 18 kD, respectively. At least 3 genes, calcineurin A-alpha (CALNA1), calcineurin A-beta (CALNA2), and calcineurin A-gamma (CALNA3), have been cloned for the catalytic subunit. The protein phosphatase (PP) holoenzyme is a trimeric complex composed of a regulatory subunit, a variable subunit and a catalytic subunit. Four major families of protein phosphatase catalytic subunits have been identified and are designated PP1, PP2A, PP2B (calcineurin) and PP2C. The PP1 family comprises subfamily members PP1-alpha, PP1-beta and PP1-gamma. The PP2A family comprises subfamily members PP2A-alpha and PP2A-beta. The PP2B family comprises subfamily members PP2B-A-alpha, PP2B-A-beta and PP2B-A-gamma. The PP2C family comprises PP2C-alpha, PP2C-beta and PP2C-gamma. Wip1, a protein identified in the p53 DNA response pathway, has also been identified as a potential member of the PP2C family. Regulatory subunits include nuclear inhibitor of PP1 (NIPP1), PP2A-A-alpha and -A-beta, PP2A-B-alpha, -B-beta and -B-gamma, PP2A-C-alpha and -C-beta, PP2A-B56-alpha and -B56-beta, PR48 and PP2B-B1 and -B2. PP-1A is one of the three catalytic subunits of protein phosphatase 1 (PP1) . PP1 is a serine/threonine specific protein phosphatase known to be involved in the regulation of a variety of cellular processes, such as cell division, glycogen metabolism, muscle contractility, protein synthesis, and HIV-1 viral transcription.