Q6DE87 (CHK1_XENLA) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Serine/threonine-protein kinase Chk1
EC=2.7.11.1

Alternative name(s):
CHK1 checkpoint homolog
Checkpoint kinase-1
Short name=xChk1

Gene names

Name:	chek1
Synonyms:	chk1

Organism

Xenopus laevis (African clawed frog)

Taxonomic identifier

8355 [NCBI]

Taxonomic lineage

Eukaryota › Metazoa › Chordata › Craniata › Vertebrata › Euteleostomi › Amphibia › Batrachia › Anura › Mesobatrachia › Pipoidea › Pipidae › Xenopodinae › Xenopus › Xenopus

Protein attributes

Sequence length	474 AA.
Sequence status	Complete.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	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]. Phosphorylates wee1 at 'Ser-549' and cdc25c at 'Ser-287', which creates binding sites for 14-3-3 proteins which activate wee1 and inhibit cdc25c. Phosphorylates cdc25a at 'Ser-504' which prevents the interaction of cdc25a with CDK2-cyclin E1, CDC2-cyclin A1 and CDC2-cyclin B1. This inhibitory effect does not require 14-3-3 protein binding. Activation of wee1 and inhibition of CDC25 results in increased inhibitory tyrosine phosphorylation of CDK-cyclin complexes and consequent inhibition of cell cycle progression. May promote DNA repair, regulate chromatin assembly and the transcription of genes that regulate cell-cycle progression. May also play a role in replication fork maintenance. Ref.1 Ref.2 Ref.3 Ref.6 Ref.7 Ref.8 Ref.9 Ref.10 Ref.13 Ref.14
Catalytic activity	ATP + a protein = ADP + a phosphoprotein.
Enzyme regulation	Activated through phosphorylation by atr or atm in response to DNA damage or inhibition of DNA replication By similarity. Ref.6
Subunit structure	Interacts with and phosphorylates clspn, an adapter protein that regulates the ATR-dependent phosphorylation of chek1. Ref.7 Ref.11 Ref.12 Ref.15
Subcellular location	Nucleus. Cytoplasm. Cytoplasm › cytoskeleton › centrosome By similarity Ref.8 Ref.16.
Developmental stage	Expressed throughout development. Transiently activated by ATR-mediated phosphorylation from the midblastula transition (MBT) to the initial gastrula stage. Developmentally regulated activation of the DNA replication checkpoint may occur as the nucleo-cytoplasmic ratio increases and maternal replication factors are depleted. Elongation of the embryonic cell cycle may allow time for the transcription of genes that initiate the switch from maternal to zygotic control of embryogenesis. Ref.2 Ref.3 Ref.10 Ref.13 Ref.14
Domain	The autoinhibitory region (AIR) binds to the kinase domain and inhibits its activity. Ref.11 Ref.16
Post-translational modification	Phosphorylated by atm in response to ionizing irradiation By similarity. Phosphorylated by atr at Thr-314, Ser-344, Ser-356 and Ser-365 in response to various stimuli that cause checkpoint activation. Phosphorylation impairs binding of the C-terminal autoinhibitory region (AIR) to the kinase domain and thereby enhances kinase activity. Ref.1 Ref.3 Ref.6 Ref.7 Ref.8 Ref.11 Ref.13 Ref.15 Ref.16
Sequence similarities	Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. NIM1 subfamily. Contains 1 protein kinase domain.

Ontologies

Keywords
Biological process	Cell cycle DNA damage
Cellular component	Cytoplasm Cytoskeleton Nucleus
Ligand	ATP-binding Nucleotide-binding
Molecular function	Developmental protein Kinase Serine/threonine-protein kinase Transferase
PTM	Phosphoprotein
Gene Ontology (GO)
Biological process	DNA damage checkpoint Inferred from sequence or structural similarity. Source: UniProtKB DNA damage induced protein phosphorylation Inferred from sequence or structural similarity. Source: UniProtKB cell cycle Inferred from electronic annotation. Source: UniProtKB-KW chromatin-mediated maintenance of transcription Inferred from sequence or structural similarity. Source: UniProtKB multicellular organismal development Inferred from electronic annotation. Source: UniProtKB-KW negative regulation of mitosis Inferred from sequence or structural similarity. Source: UniProtKB regulation of double-strand break repair via homologous recombination Inferred from sequence or structural similarity. Source: UniProtKB regulation of histone H3-K9 acetylation Inferred from sequence or structural similarity. Source: UniProtKB regulation of mitotic centrosome separation Inferred from sequence or structural similarity. Source: UniProtKB regulation of transcription from RNA polymerase II promoter in response to UV-induced DNA damage Inferred from sequence or structural similarity. Source: UniProtKB
Cellular component	centrosome Inferred from sequence or structural similarity. Source: UniProtKB chromatin Inferred from sequence or structural similarity. Source: UniProtKB condensed nuclear chromosome Inferred from sequence or structural similarity. Source: UniProtKB
Molecular function	ATP binding Inferred from electronic annotation. Source: UniProtKB-KW histone kinase activity (H3-T11 specific) Inferred from sequence or structural similarity. Source: UniProtKB
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Chain	1 – 474	474	Serine/threonine-protein kinase Chk1		PRO_0000085852
Regions
	Domain	9 – 265	257	Protein kinase
	Nucleotide binding	15 – 23	9	ATP By similarity
	Region	1 – 265	265	Interaction with CLSPN
	Region	360 – 474	115	Autoinhibitory region
	Region	367 – 474	108	Required for nuclear localization
Sites
	Active site	130	1	Proton acceptor By similarity
	Binding site	38	1	ATP By similarity
Amino acid modifications
	Modified residue	314	1	Phosphothreonine; by ATR Ref.6
	Modified residue	344	1	Phosphoserine; by ATR Ref.6 Ref.11 Ref.13 Ref.15 Ref.16
	Modified residue	356	1	Phosphoserine; by ATR Ref.6
	Modified residue	365	1	Phosphoserine; by ATR Ref.6
Experimental info
	Mutagenesis	54	1	K → A: Abolishes interaction with CLSPN. Abrogates phosphorylation at S-344 and kinase activation during checkpoint signaling. Ref.11
	Mutagenesis	129	1	R → A: Abolishes interaction with CLSPN, abrogates phosphorylation at S-344 and abolishes kinase activity. Ref.11
	Mutagenesis	135	1	N → A: Abolishes kinase activity; no effect on interaction with CLSPN. Ref.1 Ref.7 Ref.11
	Mutagenesis	148	1	D → A: Abolishes kinase activity. Ref.2
	Mutagenesis	153	1	T → A: Abolishes interaction with CLSPN. Abrogates phosphorylation at S-344 and kinase activation during checkpoint signaling. Ref.11
	Mutagenesis	162	1	R → A: Abolishes interaction with CLSPN and kinase activation during checkpoint signaling. No effect on phosphorylation at S-344. Ref.11
	Mutagenesis	314	1	T → A: Abrogates phosphorylation and activation during checkpoint signaling; when associated with A-344; A-356 and A-365. Ref.7 Ref.16
	Mutagenesis	314	1	T → D: Impairs autoinhibition by the AIR domain; when associated with D-344; D-356 and D-365. Ref.7 Ref.16
	Mutagenesis	314	1	T → E: Impairs autoinhibition by the AIR domain; when associated with E-344; E-356 and E-365. Ref.7 Ref.16
	Mutagenesis	344	1	S → A: Abrogates phosphorylation and activation during checkpoint signaling; when associated with A-314; A-356 and A-365. Ref.7 Ref.16
	Mutagenesis	344	1	S → D: Impairs autoinhibition by the AIR domain; when associated with D-314; D-356 and D-365. Ref.7 Ref.16
	Mutagenesis	344	1	S → E: Impairs autoinhibition by the AIR domain; when associated with E-314; E-356 and E-365. Ref.7 Ref.16
	Mutagenesis	356	1	S → A: Abrogates phosphorylation and activation during checkpoint signaling; when associated with A-314; A-344 and A-365. Ref.7 Ref.16
	Mutagenesis	356	1	S → D: Impairs autoinhibition by the AIR domain; when associated with D-314; D-344 and D-365. Ref.7 Ref.16
	Mutagenesis	356	1	S → E: Impairs autoinhibition by the AIR domain; when associated with E-314; E-344 and E-365. Ref.7 Ref.16
	Mutagenesis	365	1	S → A: Abrogates phosphorylation and activation during checkpoint signaling; when associated with A-314; A-344 and A-356. Ref.7 Ref.16
	Mutagenesis	365	1	S → D: Impairs autoinhibition by the AIR domain; when associated with D-314; D-344 and D-356. Ref.7 Ref.16
	Mutagenesis	365	1	S → E: Impairs autoinhibition by the AIR domain; when associated with E-314; E-344 and E-356. Ref.7 Ref.16
	Mutagenesis	374 – 380	7	Missing: Induces hyperphosphorylation and enhances kinase activity. Ref.5
	Mutagenesis	374 – 375	2	KR → AA: Impairs autoinhibition and abrogates nuclear localization.
	Mutagenesis	377	1	T → A: Induces hyperphosphorylation and enhances kinase activity and cell cycle arrest. Abolishes interaction with CLSPN. Ref.5 Ref.11
	Mutagenesis	377	1	T → E: Enhances kinase activity. Ref.5 Ref.11
	Mutagenesis	451 – 452	2	KR → AA: Enhances kinase activity.
	Mutagenesis	456 – 458	3	KIK → AAA: Enhances kinase activity and abrogates nuclear localization. Ref.16
	Sequence conflict	165	1	N → S in AAC64262. Ref.1
	Sequence conflict	165	1	N → S in BAA34058. Ref.2
	Sequence conflict	230 – 231	2	Missing in BAA34058. Ref.2
	Sequence conflict	232	1	K → E in AAF00098. Ref.3
	Sequence conflict	238	1	P → L in BAA34058. Ref.2
	Sequence conflict	243	1	C → G in AAC64262. Ref.1
	Sequence conflict	243	1	C → G in BAA34058. Ref.2
	Sequence conflict	307	1	Missing in AAF00098. Ref.3
	Sequence conflict	307	1	Missing in AAH77249. Ref.4
	Sequence conflict	331 – 333	3	YID → DIN in AAC64262. Ref.1
	Sequence conflict	331 – 333	3	YID → DIN in BAA34058. Ref.2
	Sequence conflict	472 – 473	2	PD → SA in AAC64262. Ref.1
	Sequence conflict	472 – 473	2	PD → SA in BAA34058. Ref.2

Sequences

	Sequence		Length	Mass (Da)
	Q6DE87 [UniParc]. Last modified September 27, 2005. Version 2. Checksum: B6D09B14838F1C0A	FASTA	474	53,975
	10 20 30 40 50 60 MAVPFVEDWD LVQTLGEGAY GEVQLAVNRK TEEAVAVKIV DMTRAADCPE NIKKEICINR 70 80 90 100 110 120 MLSHTNIVRF YGHRREGNIQ YLFLEYCRGG ELFDRIEPDV GMPEQDAQKF FQQLIAGVEY 130 140 150 160 170 180 LHSIGITHRD IKPENLLLDE RDQLKISDFG LATVFRHNGK ERLLNKMCGT LPYVAPELIK 190 200 210 220 230 240 SRAFHADPVD VWSCGIVLTA MLAGELPWDQ PNEVCQEYCD WKEKNHYLTP WKKISATPLA 250 260 270 280 290 300 LLCKMLTENP QSRITIPDIK KDRWFTEIIK KGLKRSRVIS GGSSDSSVLC KQIRSDIDIS 310 320 330 340 350 360 HFSHSEEKTA LSSTQPEPRT ALATWDSNSS YIDNLVQGKG ISFSQPACPD NMLLNSQLIG 370 380 390 400 410 420 TPGSSQNVWQ RLVKRMTRFF TKVNAESSYS NLMDTCEKMG YVLKKSCANE VTLSTTDRRN 430 440 450 460 470 NKLIFKVNLV EMEDRILLDF RLSKGDGLEF KRHFLKIKKK MDAVVAVQKV LPDT

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"The Xenopus Chk1 protein kinase mediates a caffeine-sensitive pathway of checkpoint control in cell-free extracts." Kumagai A., Guo Z., Emami K.H., Wang S.X., Dunphy W.G. J. Cell Biol. 142:1559-1569(1998) [PubMed: 9744884] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, PHOSPHORYLATION, MUTAGENESIS OF ASN-135.
[2]	"Involvement of Chk1 kinase in prophase I arrest of Xenopus oocytes." Nakajo N., Oe T., Uto K., Sagata N. Dev. Biol. 207:432-444(1999) [PubMed: 10068474] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, DEVELOPMENTAL STAGE, MUTAGENESIS OF ASP-148. Tissue: Ovary.
[3]	"Dissection of the XChk1 signaling pathway in Xenopus laevis embryos." Kappas N.C., Savage P., Chen K.C., Walls A.T., Sible J.C. Mol. Biol. Cell 11:3101-3108(2000) [PubMed: 10982403] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, DEVELOPMENTAL STAGE, PHOSPHORYLATION.
[4]	NIH - Xenopus Gene Collection (XGC) project Submitted (JUL-2004) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA]. Tissue: Ovary.
[5]	"Activation of Xenopus Chk1 by mutagenesis of threonine-377." Wang S.X., Dunphy W.G. FEBS Lett. 487:277-281(2000) [PubMed: 11150524] [Abstract] Cited for: MUTAGENESIS OF 374-LYS--PHE-380 AND THR-377.
[6]	"Requirement for Atr in phosphorylation of Chk1 and cell cycle regulation in response to DNA replication blocks and UV-damaged DNA in Xenopus egg extracts." Guo Z., Kumagai A., Wang S.X., Dunphy W.G. Genes Dev. 14:2745-2756(2000) [PubMed: 11069891] [Abstract] Cited for: FUNCTION, ENZYME REGULATION, PHOSPHORYLATION AT THR-314; SER-344; SER-356 AND SER-365.
[7]	"Claspin, a novel protein required for the activation of Chk1 during a DNA replication checkpoint response in Xenopus egg extracts." Kumagai A., Dunphy W.G. Mol. Cell 6:839-849(2000) [PubMed: 11090622] [Abstract] Cited for: FUNCTION, INTERACTION WITH CLSPN, PHOSPHORYLATION, MUTAGENESIS OF ASN-135; THR-314; SER-344; SER-356 AND SER-365.
[8]	"Cytoplasmic occurrence of the Chk1/Cdc25 pathway and regulation of Chk1 in Xenopus oocytes." Oe T., Nakajo N., Katsuragi Y., Okazaki K., Sagata N. Dev. Biol. 229:250-261(2001) [PubMed: 11133168] [Abstract] Cited for: FUNCTION, SUBCELLULAR LOCATION, PHOSPHORYLATION, AUTOINHIBITION.
[9]	"Positive regulation of Wee1 by Chk1 and 14-3-3 proteins." Lee J., Kumagai A., Dunphy W.G. Mol. Biol. Cell 12:551-563(2001) [PubMed: 11251070] [Abstract] Cited for: FUNCTION.
[10]	"Chk1 is activated transiently and targets Cdc25A for degradation at the Xenopus midblastula transition." Shimuta K., Nakajo N., Uto K., Hayano Y., Okazaki K., Sagata N. EMBO J. 21:3694-3703(2002) [PubMed: 12110582] [Abstract] Cited for: FUNCTION, DEVELOPMENTAL STAGE.
[11]	"Phosphorylated claspin interacts with a phosphate-binding site in the kinase domain of Chk1 during ATR-mediated activation." Jeong S.-Y., Kumagai A., Lee J., Dunphy W.G. J. Biol. Chem. 278:46782-46788(2003) [PubMed: 12963733] [Abstract] Cited for: DOMAIN FOR INTERACTION WITH CLSPN, PHOSPHORYLATION AT SER-344, MUTAGENESIS OF LYS-54; ARG-129; ASN-135; THR-153; ARG-162 AND THR-377.
[12]	"Repeated phosphopeptide motifs in claspin mediate the regulated binding of Chk1." Kumagai A., Dunphy W.G. Nat. Cell Biol. 5:161-165(2003) [PubMed: 12545175] [Abstract] Cited for: INTERACTION WITH CLSPN.
[13]	"The DNA damage checkpoint in embryonic cell cycles is dependent on the DNA-to-cytoplasmic ratio." Conn C.W., Lewellyn A.L., Maller J.L. Dev. Cell 7:275-281(2004) [PubMed: 15296723] [Abstract] Cited for: FUNCTION, DEVELOPMENTAL STAGE, PHOSPHORYLATION AT SER-344.
[14]	"Chk1, but not Chk2, inhibits Cdc25 phosphatases by a novel common mechanism." Uto K., Inoue D., Shimuta K., Nakajo N., Sagata N. EMBO J. 23:3386-3396(2004) [PubMed: 15272308] [Abstract] Cited for: FUNCTION, DEVELOPMENTAL STAGE.
[15]	"Claspin and the activated form of ATR-ATRIP collaborate in the activation of Chk1." Kumagai A., Kim S.-M., Dunphy W.G. J. Biol. Chem. 279:49599-49608(2004) [PubMed: 15371427] [Abstract] Cited for: INTERACTION WITH CLSPN, PHOSPHORYLATION AT SER-344.
[16]	"Regulation of Chk1 kinase by autoinhibition and ATR-mediated phosphorylation." Katsuragi Y., Sagata N. Mol. Biol. Cell 15:1680-1689(2004) [PubMed: 14767054] [Abstract] Cited for: SUBCELLULAR LOCATION, DOMAIN AIR, PHOSPHORYLATION AT SER-344, MUTAGENESIS OF THR-314; SER-344; SER-356; SER-365; 374-LYS-ARG-375; 451-LYS-ARG-452 AND 456-LYS--LYS-458.

Cross-references

Sequence databases
EMBL GenBank DDBJ	AF053120 mRNA. Translation: AAC64262.1. AB019218 mRNA. Translation: BAA34058.1. AF117816 mRNA. Translation: AAF00098.1. BC077249 mRNA. Translation: AAH77249.1.
RefSeq	NP_001082039.1. NM_001088570.1.
UniGene	Xl.406.
3D structure databases
ProteinModelPortal	Q6DE87.
SMR	Q6DE87. Positions 3-272.
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Genome annotation databases
GeneID	398191.
KEGG	xla:398191.
Organism-specific databases
CTD	1111.
Xenbase	XB-GENE-866102. chek1.
Phylogenomic databases
HOVERGEN	HBG002590.
Family and domain databases
InterPro	IPR011009. Kinase-like_dom. IPR000719. Prot_kinase_cat_dom. IPR017441. Protein_kinase_ATP_BS. IPR017442. Se/Thr_kinase-like_dom. IPR008271. Ser/Thr_kinase_AS. IPR002290. Ser/Thr_kinase_dom. [Graphical view]
KO	K02216.
Pfam	PF00069. Pkinase. 1 hit. [Graphical view]
SMART	SM00220. S_TKc. 1 hit. [Graphical view]
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. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

CHK1_XENLA

Accession

Primary (citable) accession number: Q6DE87
Secondary accession number(s): Q78CK1, Q78DQ2, Q9YI18

Entry history

Integrated into UniProtKB/Swiss-Prot:	September 27, 2005
Last sequence update:	September 27, 2005
Last modified:	December 14, 2011
This is version 66 of the entry and version 2 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Chordata Protein Annotation Program