POLA1

POLA1 is the catalytic subunit of DNA polymerase, which together with a regulatory and two primase subunits, forms the DNA polymerase alpha complex. The catalytic subunit plays an essential role in the initiation of DNA replication.

DNA Polymerase Alpha 1, Catalytic Subunit

Catalytic subunit of the DNA polymerase alpha complex (also known as the alpha DNA polymerase-primase complex) which plays an essential role in the initiation of DNA synthesis. During the S phase of the cell cycle, the DNA polymerase alpha complex (composed of a catalytic subunit POLA1, a regulatory subunit POLA2 and two primase subunits PRIM1 and PRIM2) is recruited to DNA at the replicative forks via direct interactions with MCM10 and WDHD1. The primase subunit of the polymerase alpha complex initiates DNA synthesis by oligomerising short RNA primers on both leading and lagging strands. These primers are initially extended by the polymerase alpha catalytic subunit and subsequently transferred to polymerase delta and polymerase epsilon for processive synthesis on the lagging and leading strand, respectively. The reason this transfer occurs is because the polymerase alpha has limited processivity and lacks intrinsic 3' exonuclease activity for proofreading error, and therefore is not well suited for replicating long complexes. In the cytosol, responsible for a substantial proportion of the physiological concentration of cytosolic RNA:DNA hybrids, which are necessary to prevent spontaneous activation of type I interferon responses (PubMed:27019227).

DNA repairManual Assertion Based On ExperimentIMP:UniProtKB
DNA replicationManual Assertion Based On ExperimentIMP:UniProtKB
DNA replication initiationManual Assertion Based On ExperimentIDA:UniProtKB
DNA replication, synthesis of RNA primerManual Assertion Based On ExperimentIDA:UniProtKB
DNA strand elongation involved in DNA replicationManual Assertion Based On ExperimentIMP:UniProtKB
DNA synthesis involved in DNA repairManual Assertion Based On ExperimentIMP:UniProtKB
Double-strand break repair via nonhomologous end joiningManual Assertion Based On ExperimentIMP:UniProtKB
Lagging strand elongationManual Assertion Based On ExperimentIDA:UniProtKB
Leading strand elongationManual Assertion Based On ExperimentIDA:UniProtKB
Mitotic DNA replication initiationManual Assertion Based On ExperimentIBA:GO_Central
Regulation of type I interferon productionManual Assertion Based On ExperimentIMP:UniProtKB

Nucleus
Cytoplasm, cytosol
In the cytosol, colocalizes with RNA:DNA hybrids with a speckled pattern.

Pigmentary disorder, reticulate, with systemic manifestations, X-linked (PDR):
An X-linked recessive disorder characterized by recurrent infections and sterile inflammation in various organs. Diffuse skin hyperpigmentation with a distinctive reticulate pattern is universally evident by early childhood. This is later followed in many patients by hypohidrosis, corneal inflammation and scarring, enterocolitis that resembles inflammatory bowel disease, and recurrent urethral strictures. Melanin and amyloid deposition is present in the dermis. Affected males also have a characteristic facies with frontally upswept hair and flared eyebrows. Female carriers have only restricted pigmentary changes along Blaschko's lines.
Van Esch-O'Driscoll syndrome (VEODS):
An X-linked recessive syndrome characterized by different degrees of intellectual disability, moderate to severe short stature, microcephaly, hypogonadism, and variable congenital malformations.

A 165 kDa form is probably produced by proteolytic cleavage at Lys-124.