CHK1, active

CHK1, active

Upstate (Millipore)

10 µg

N-terminal GST tagged, human full length CHK1

Kinase Assay

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FUNCTION: SwissProt: O14757 # Required for checkpoint mediated cell cycle arrest in response to DNA damage or the presence of unreplicated DNA. May also negatively regulate cell cycle progression during unperturbed cell cycles. Recognizes the substrate consensus sequence [R-X-X- S/T]. Binds to and phosphorylates CDC25A, CDC25B and CDC25C. Phosphorylation of CDC25A at 'Ser-178' and 'Thr-507' and phosphorylation of CDC25C at 'Ser-216' creates binding sites for 14-3-3 proteins which inhibit CDC25A and CDC25C. Phosphorylation of CDC25A at 'Ser-76', 'Ser-124', 'Ser-178', 'Ser-279' and 'Ser- 293' promotes proteolysis of CDC25A. Inhibition of CDC25 activity leads to increased inhibitory tyrosine phosphorylation of CDK- cyclin complexes and blocks cell cycle progression. Binds to and phosphorylates RAD51 at 'Thr-309', which may enhance the association of RAD51 with chromatin and promote DNA repair by homologous recombination. Binds to and phosphorylates TLK1 at 'Ser-743', which prevents the TLK1-dependent phosphorylation of the chromatin assembly factor ASF1A. This may affect chromatin assembly during S phase or DNA repair. May also phosphorylate multiple sites within the C-terminus of TP53, which promotes activation of TP53 by acetylation and enhances suppression of cellular proliferation.


SIZE: 476 amino acids; 54420 Da

SUBUNIT: Interacts with BRCA1, CLSPN, PPM1D, RAD51, TIMELESS, XPO1/CRM1 and YWHAZ/14-3-3 zeta.

SUBCELLULAR LOCATION: Nucleus. Cytoplasm. Note=Nuclear export is mediated at least in part by XPO1/CRM1. Also localizes to the centrosome specifically during interphase, where it may protect centrosomal CDC2 kinase from inappropriate activation by cytoplasmic CDC25B.

TISSUE SPECIFICITY: Expressed ubiquitously with the most abundant expression in thymus, testis, small intestine and colon.


DOMAIN: SwissProt: O14757 The autoinhibitory region (AIR) inhibits the activity of the kinase domain.

PTM: Phosphorylated by ATR in a RAD17-dependent manner in response to ultraviolet irradiation and inhibition of DNA replication. Phosphorylated by ATM in response to ionizing irradiation. ATM and ATR can both phosphorylate Ser-317 and Ser-345 and this results in enhanced kinase activity. Phosphorylation at Ser-345 also increases binding to 14-3-3 proteins and promotes nuclear retention. Conversely, dephosphorylation at Ser-345 by PPM1D may contribute to exit from checkpoint mediated cell cycle arrest. May also be phosphorylated at Ser-280 by AKT1/PKB, which may promote mono and/or diubiquitination. Also phosphorylated at undefined residues during mitotic arrest, which results in decreased activity. & Ubiquitinated. Mono or diubiquitination promotes nuclear exclusion (By similarity).


SIMILARITY: Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. NIM1 subfamily. & Contains 1 protein kinase domain.

Human

81.6kDa

routinely evaluated by phosphorylation of the CHKtide substrate peptide

Upstate

expressed in SF21 cells

CHK1

O14757

For Specific Activity data, refer to the Certificate of Analysis for individual lots of this enzyme.

1 year at -70C

CAMK

This enzyme is part of KinaseProfiler™, a custom inhibitor selectivity discovery service.

Also available in 250 µg size --call for pricing and availability and reference catalog number 14-346M when ordering the 250 µg size.

• CHEK1
• CHK1

• Kinases
• Signal Transduction

CHK1, active

NM_001274.3

Glutathione-agarose