Q91ZN7 (CHK1_RAT) Reviewed, UniProtKB/Swiss-Prot
Last modified May 1, 2013. Version 97. History...
Names and origin
|Protein names||Recommended name:|
Serine/threonine-protein kinase Chk1
CHK1 checkpoint homolog
|Organism||Rattus norvegicus (Rat) [Reference proteome]|
|Taxonomic identifier||10116 [NCBI]|
|Taxonomic lineage||Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Mammalia › Eutheria › Euarchontoglires › Glires › Rodentia › Sciurognathi › Muroidea › Muridae › Murinae › Rattus|
|Sequence length||476 AA.|
|Protein existence||Evidence at transcript level|
General annotation (Comments)
Serine/threonine-protein kinase which is required for checkpoint-mediated cell cycle arrest and activation of DNA repair in response to the presence of DNA damage or unreplicated DNA. May also negatively regulate cell cycle progression during unperturbed cell cycles. This regulation is achieved by a number of mechanisms that together help to preserve the integrity of the genome. Recognizes the substrate consensus sequence [R-X-X-S/T]. Binds to and phosphorylates CDC25A, CDC25B and CDC25C. This inhibits their activity through proteasomal degradation, nucleo-cytoplasmic shuttling and inhibition by proteins of the 13-3-3 family. Inhibition of CDC25 leads to increased inhibitory tyrosine phosphorylation of CDK-cyclin complexes and blocks cell cycle progression. Also phosphorylates NEK6. Binds to and phosphorylates RAD51 at 'Thr-309', which promotes the release of RAD51 from BRCA2 and enhances the association of RAD51 with chromatin, thereby promoting DNA repair by homologous recombination. Phosphorylates multiple sites within the C-terminus of TP53, which promotes activation of TP53 by acetylation and promotes cell cycle arrest and suppression of cellular proliferation. Also promotes repair of DNA cross-links through phosphorylation of FANCE. Binds to and phosphorylates TLK1, which prevents the TLK1-dependent phosphorylation of the chromatin assembly factor ASF1A. This may enhance chromatin assembly both in the presence or absence of DNA damage. May also play a role in replication fork maintenance through regulation of PCNA. May regulate the transcription of genes that regulate cell-cycle progression through the phosphorylation of histones. Phosphorylates histone H3.1 (to form H3T11ph), which leads to epigenetic inhibition of a subset of genes. May also phosphorylate RB1 to promote its interaction with the E2F family of transcription factors and subsequent cell cycle arrest By similarity.
ATP + a protein = ADP + a phosphoprotein.
Activated through phosphorylation predominantly by ATR but also by ATM in response to DNA damage or inhibition of DNA replication. Activation is modulated by several mediators including CLSPN, BRCA1 and FEM1B By similarity.
Interacts (phosphorylated by ATR) with RAD51. Interacts with and phosphorylates CLSPN, an adapter protein that regulates the ATR-dependent phosphorylation of CHEK1. Interacts with BRCA1. Interacts with and phosphorylates CDC25A, CDC25B and CDC25C. Interacts with FBXO6, which regulates CHEK1. Interacts with PPM1D, which regulates CHEK1 through dephosphorylation. Interacts with TIMELESS; DNA damage-dependent. Interacts with FEM1B; activates CHEK1 in response to stress. Interacts with TLK1. Interacts with XPO1 and YWHAZ By similarity.
Nucleus By similarity. Cytoplasm By similarity. Cytoplasm › cytoskeleton › centrosome By similarity. 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 By similarity.
The autoinhibitory region (AIR) inhibits the activity of the kinase domain By similarity.
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 induces a change in the conformation of the protein, activates the kinase activity and is a prerequisite for interaction with FBXO6 and subsequent ubiquitination at Lys-436. 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. Phosphorylation at Ser-280 by AKT1/PKB, may promote mono and/or diubiquitination. Also phosphorylated at undefined residues during mitotic arrest, resulting in decreased activity By similarity.
Ubiquitinated. Mono or diubiquitination promotes nuclear exclusion. The activated form (phosphorylated on Ser-345) is polyubiquitinated at Lys-436 by some SCF-type E3 ubiquitin ligase complex containing FBXO6 promoting its degradation. Ubiquitination and degradation are required to terminate the checkpoint and ensure that activated CHEK1 does not accumulate as cells progress through S phase, when replication forks encounter transient impediments during normal DNA replication By similarity.
Contains 1 protein kinase domain.
|This entry describes 2 isoforms produced by alternative promoter usage. [Align] [Select]|
|Isoform 1 (identifier: Q91ZN7-1) |
This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.
|Isoform 2 (identifier: Q91ZN7-2) |
The sequence of this isoform differs from the canonical sequence as follows:
Sequence annotation (Features)
|Feature key||Position(s)||Length||Description||Graphical view||Feature identifier|
|Chain||1 – 476||476||Serine/threonine-protein kinase Chk1||PRO_0000085850|
|Domain||9 – 265||257||Protein kinase|
|Nucleotide binding||15 – 23||9||ATP By similarity|
|Region||1 – 265||265||Interaction with CLSPN By similarity|
|Region||391 – 476||86||Autoinhibitory region By similarity|
|Active site||130||1||Proton acceptor By similarity|
|Binding site||38||1||ATP By similarity|
Amino acid modifications
|Modified residue||280||1||Phosphoserine; by PKB/AKT1 By similarity|
|Modified residue||286||1||Phosphoserine By similarity|
|Modified residue||296||1||Phosphoserine By similarity|
|Modified residue||301||1||Phosphoserine By similarity|
|Modified residue||317||1||Phosphoserine; by ATM and ATR By similarity|
|Modified residue||345||1||Phosphoserine; by ATM and ATR By similarity|
|Cross-link||436||Glycyl lysine isopeptide (Lys-Gly) (interchain with G-Cter in ubiquitin) By similarity|
|Alternative sequence||1 – 282||282||Missing in isoform 2.||VSP_015770|
|||"Cloning and characterization of liver-specific isoform of Chk1 gene from rat."|
Shann Y.-J., Hsu M.-T.
J. Biol. Chem. 276:48863-48870(2001) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORMS 1 AND 2), ALTERNATIVE PROMOTER USAGE, TISSUE SPECIFICITY.
|||"The rat homolog of checkpoint kinase chk1."|
Wang X., Wang Y.
Submitted (NOV-2001) to the EMBL/GenBank/DDBJ databases
Cited for: NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM 1).
Strain: Fischer 344.
|+||Additional computationally mapped references.|
|AF414135 mRNA. Translation: AAK98619.1.|
AF414136 mRNA. Translation: AAK98620.1.
AF443592 mRNA. Translation: AAL37894.1.
|RefSeq||NP_536325.1. NM_080400.1. |
3D structure databases
|SMR||Q91ZN7. Positions 3-273. |
Protocols and materials databases
Genome annotation databases
|Ensembl||ENSRNOT00000011226; ENSRNOP00000011226; ENSRNOG00000008181. |
|UCSC||RGD:620545. rat. |
|RGD||620545. Chek1. |
Enzyme and pathway databases
Gene expression databases
|GermOnline||ENSRNOG00000008181. Rattus norvegicus. |
Family and domain databases
|InterPro||IPR011009. Kinase-like_dom. |
|Pfam||PF00069. Pkinase. 1 hit. |
|SMART||SM00220. S_TKc. 1 hit. |
|SUPFAM||SSF56112. Kinase_like. 1 hit. |
|PROSITE||PS00107. PROTEIN_KINASE_ATP. 1 hit. |
PS50011. PROTEIN_KINASE_DOM. 1 hit.
PS00108. PROTEIN_KINASE_ST. 1 hit.
|Accession||Primary (citable) accession number: Q91ZN7|
Secondary accession number(s): Q91ZN6
|Entry status||Reviewed (UniProtKB/Swiss-Prot)|
|Annotation program||Chordata Protein Annotation Program|
Index of protein domains and families