NUC194
SMART ACC:	SM001344
Description:	This is domain B in the catalytic subunit of DNA-dependent protein kinases.
InterPro ACC:	IPR012582
InterPro abstract:	This domain represents a region of the Circular Cradle segment (CC) from DNA-PKcs that covers the complete CC3 and part of CC4. This domain contains the Ku-binding site A and a the highly conserved region (HCR) II [ PUBMED:28154079 ]. DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is involved in … expand This domain represents a region of the Circular Cradle segment (CC) from DNA-PKcs that covers the complete CC3 and part of CC4. This domain contains the Ku-binding site A and a the highly conserved region (HCR) II [ PUBMED:28154079 ]. DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is involved in DNA nonhomologous end joining (NHEJ), which is recruited by Ku70/80 heterodimer to DNA ends and required for double-strand break (DSB) repair. DNA-PKcs phosphorylates a number of protein substrates, including the heat shock protein 90 (HSP90), the transcription factors p53, specificity protein 1 (Sp1) and MYC23, and a majority of NHEJ factors. It folds into three well-defined large structural units, consisting of a N-terminal region (arranged in four supersecondary α-helical structures, N1 to N4), the Circular Cradle (consisting of five supersecondary α-helical structures CC1 to CC5), and the C-terminal Head (comprising FAT, FRB, kinase, and FATC). The N-terminal and CCs regions resemble HEAT repeats, and thus, they are also referred to as N-HEAT and M-HEAT ('middle'), respectively. The N-terminal region likely mediates DNA binding and, together with the CCs, forms a ring through which Ku70/80 may present DNA for repair. The CCs form a curved elliptical ring that serves as a scaffold to maintain the integrity of the whole complex. It has been suggested that the binding of Ku or DNA activates the allosteric mechanism required for communication between the N terminus and the CC with the kinase in the Head [ PUBMED:28154079 PUBMED:28652322 PUBMED:28840859 PUBMED:33077952 ]. collapse
GO process:	double-strand break repair via nonhomologous end joining (GO:0006303)
GO component:	nucleus (GO:0005634)
Family alignment:	View the Family alignment or the Alignment consensus sequence
There are 703 NUC194 domains in 703 proteins in SMART's NRDB database.

Taxonomic distribution of proteins containing NUC194 domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing NUC194 domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Relevant references for this domain

Primary literature for the NUC194 domain is listed below. Automatically-derived, secondary literature is also available.

KEGG pathways involving proteins which contain this domain

This information is based on the mapping of SMART genomic protein database to KEGG orthologous groups. Percentages are related to the number of proteins containing a NUC194 domain which could be assigned to a KEGG orthologous group, and not all proteins containing NUC194 domains. Please note that proteins can be included in multiple pathways, ie. the numbers below will not add to 100%.

KEGG pathways

KEGG orthologous groups

3D structures in PDB containing this domain

Links to other resources describing this domain

InterPro	IPR012582
Pfam	NUC194