CST, 2348S, Phospho-Chk1 (Ser345) (133D3) Rabbit Monoclonal Antibody

Monoclonal Antibody for studying Chk1 (Ser345) phosphate. Validated for WB,WB,IF,F. Available in 3 sizes. Highly specific and rigorously validated in-house, Phospho-Chk1 (Ser345) (133D3) Rabbit Monoclonal Antibody (CST #2348) is ready to ship. Product Usage Information Western Blotting: 1:1000 Simple Western™: 1:10 - 1:50 Immunofluorescence (Immunocytochemistry): 1:50 Flow Cytometry (Fixed/Permeabilized): 1:200 Storage Supplied in 10 mM sodium HEPES (pH 7.5), 150 mM NaCl, 100 µg/ml BSA, 50% glycerol and less than 0.02% sodium azide. Store at -20°C. Do not aliquot the antibody. For a carrier free (BSA and azide free) version of this product see product # 76784 . Protocol Available protocols: Western Blotting, Immunofluorescence (Immunocytochemistry), Flow Cytometry (Fixed/Permeabilized) Specificity / Sensitivity Phospho-Chk1 (Ser345) (133D3) Rabbit Monoclonal Antibody detects endogenous levels of Chk1 only when phosphorylated at serine 345. Species Reactivity: Human, Mouse, Rat, Monkey Source / Purification Monoclonal antibody is produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Ser345 of human Chk1. Background Chk1 kinase acts downstream of ATM/ATR kinase and plays an important role in DNA damage checkpoint control, embryonic development, and tumor suppression (1). Activation of Chk1 involves phosphorylation at Ser317 and Ser345 by ATM/ATR, followed by autophosphorylation of Ser296. Activation occurs in response to blocked DNA replication and certain forms of genotoxic stress (2). While phosphorylation at Ser345 serves to localize Chk1 to the nucleus following checkpoint activation (3), phosphorylation at Ser317 along with site-specific phosphorylation of PTEN allows for re-entry into the cell cycle following stalled DNA replication (4). Chk1 exerts its checkpoint mechanism on the cell cycle, in part, by regulating the cdc25 family of phosphatases. Chk1 phosphorylation of cdc25A targets it for proteolysis and inhibits its activity through 14-3-3 binding (5). Activated Chk1 can inactivate cdc25C via phosphorylation at Ser216, blocking the activation of cdc2 and transition into mitosis (6). Centrosomal Chk1 has been shown to phosphorylate cdc25B and inhibit its activation of CDK1-cyclin B1, thereby abrogating mitotic spindle formation and chromatin condensation (7). Furthermore, Chk1 plays a role in spindle checkpoint function through regulation of aurora B and BubR1 (8). Research studies have implicated Chk1 as a drug target for cancer therapy as its inhibition leads to cell death in many cancer cell lines (9). Alternate Names Cell cycle checkpoint kinase; checkpoint kinase 1; Checkpoint kinase-1; Checkpoint, S. pombe, homolog of, 1; CHEK1; CHK1; CHK1 checkpoint homolog; CHK1 checkpoint homolog (S. pombe); Chk1-S; Serine/threonine-protein kinase Chk1 Specification REACTIVITY: H M R Mk SENSITIVITY: Endogenous MW (kDa): 56 Source/Isotype: Rabbit IgG