mouse monoclonal IgG1; PP2A-B55-α Antibody (2G9) is an IgG1 κ mouse monoclonal PP2A-B55-alpha antibody (also designated Serine/Threonine phosphatase PP2A-B55 alpha antibody, B55A antibody, PR52A antibody, PR55A antibody, B55ALPHA antibody, PR55alpha antibody, protein phosphatase 2 regulatory subunit B alpha antibody, protein phosphatase 2 (PP2A) B55 alpha antibody, PPP2R2A antibody, PP2A B55 subfamily alpha antibody, PP2A heterotrimeric (structural A, regulatory B, catalytic C) protein phosphatase antibody, PP2A phosphatase regulatory B55 alpha antibody, protein phosphatase 2 complex antibody, or Ser/Thr phosphatase antibody) that detects the PP2A-B55-alpha protein of mouse, rat, human and chicken, frog (Xenopus laevis) origin by WB, IP and IF. PP2A-B55-α Antibody (2G9) is available as both the non-conjugated anti-PP2A-B55-alpha antibody form, as well as multiple conjugated forms of anti-PP2A-B55-alpha antibody, including agarose, HRP, PE, FITC and multiple Alexa Fluor® conjugates. In eukaryotes, the phosphorylation and dephosphorylation of proteins on serine and threonine residues is an essential means of regulating a broad range of cellular functions, including division, homeostasis and apoptosis. A group of proteins that are intimately involved in this process are the protein phosphatases. In general, 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, designated PP1, PP2A, PP2B (calcineurin) and PP2C. An additional protein phosphatase catalytic subunit, PPX (also known as PP4) is a putative member of a novel PP family. The PP2A family comprises subfamily members PP2Aα and PP2Aβ. The PP2A catalytic subunit associates with a variety of regulatory subunits. The B family of regulatory subunits (including B55, B56 and PR72/130 subfamilies) is believed to participate in substrate specificity and catalytic activity. PP2A-B55, also known as PP2A regulatory subunit subfamily B55 or PP2A-B1, is a B subfamily consisting of four B55 isoforms (α, β, γ and δ) encoded by four distinct genes.