DNA polymerase alpha catalytic subunit

Polymerase (DNA directed), alpha 1, catalytic subunit
PDB rendering based on 1k0p.
Available structures PDB Ortholog search: PDBe, RCSB List of PDB id codes 1K0P​, 1K18​, 1N5G​, 4Q5V​, 4QCL​, 4Y97​
Identifiers
Symbols	POLA1 ; NSX; POLA; p180
External IDs	OMIM: 312040 MGI: 99660 HomoloGene: 6802 ChEMBL: 1828 GeneCards: POLA1 Gene
EC number	2.7.7.7
Gene ontology Molecular function • nucleotide binding • nucleoside binding • DNA binding • chromatin binding • DNA-directed DNA polymerase activity • DNA primase activity • protein binding • 3'-5' exonuclease activity • protein kinase binding • metal ion binding • protein heterodimerization activity • 4 iron, 4 sulfur cluster binding Cellular component • chromatin • nucleus • nuclear envelope • nucleoplasm • alpha DNA polymerase:primase complex • nucleolus • cytoplasm • nuclear matrix Biological process • G1/S transition of mitotic cell cycle • regulation of transcription involved in G1/S transition of mitotic cell cycle • mitotic cell cycle • telomere maintenance via recombination • telomere maintenance • DNA synthesis involved in DNA repair • DNA replication • DNA-dependent DNA replication • DNA replication, synthesis of RNA primer • DNA replication initiation • DNA strand elongation involved in DNA replication • leading strand elongation • lagging strand elongation • DNA repair • double-strand break repair via nonhomologous end joining • cell proliferation • viral process • telomere maintenance via semi-conservative replication • DNA biosynthetic process • nucleic acid phosphodiester bond hydrolysis Sources: Amigo / QuickGO
RNA expression pattern
More reference expression data
Orthologs
Species	Human	Mouse
Entrez	5422	18968
Ensembl	ENSG00000101868	ENSMUSG00000006678
UniProt	P09884	P33609
RefSeq (mRNA)	NM_016937	NM_008892
RefSeq (protein)	NP_058633	NP_032918
Location (UCSC)	Chr X: 24.69 – 25 Mb	Chr X: 93.3 – 93.63 Mb
PubMed search

DNA polymerase alpha catalytic subunit is an enzyme that in humans is encoded by the POLA1 gene.^[1]

Function

Pol α has limited processivity and lacks 3′ exonuclease activity for proofreading errors. Thus it is not well suited to efficiently and accurately copy long templates (unlike Pol Delta and Epsilon). Instead it plays a more limited role in replication. Pol α is responsible for the initiation of DNA replication at origins of replication (on both the leading and lagging strands) and during synthesis of Okazaki fragments on the lagging strand. The Pol α complex (pol α-DNA primase complex) consists of four subunits: the catalytic subunit POLA1, the regulatory subunit POLA2, and the small and the large primase subunits PRIM1 and PRIM2 respectively. Once primase has created the RNA primer, Pol α starts replication elongating the primer with ~20 nucleotides.

Interactions

DNA dependent polymerase alpha (Pol α) has been shown to interact with Retinoblastoma protein,^[2] PARP1^[3] and RBMS1.^[4]

See also

• DNA Polymerase
• DNA polymerase alpha subunit 2

References

• Simbulan CM, Suzuki M, Izuta S, Sakurai T, Savoysky E, Kojima K, Miyahara K, Shizuta Y, Yoshida S (Jan 1993). "Poly(ADP-ribose polymerase stimulates DNA polymerase alpha by physical association". J. Biol. Chem 268 (1): 93–99. PMID 8416979. 

Further reading

PDB gallery 1k0p: NMR Structures of the Zinc Finger Domain of Human DNA Polymerase-alpha  1k18: Minimized Average NMR Structure of the Zinc Finger Domain of Human DNA Polymerase-alpha  1n5g: NMR Structures of the Zinc Finger Domain of Human DNA Polymerase-alpha