NCAPH

This gene encodes a member of the barr gene family and a regulatory subunit of the condensin complex. This complex is required for the conversion of interphase chromatin into condensed chromosomes. The protein encoded by this gene is associated with mitotic chromosomes, except during the early phase of chromosome condensation. During interphase, the protein has a distinct punctate nucleolar localization. Alternatively spliced transcript variants encoding different proteins have been described. [provided by RefSeq, Jul 2013]

Full Name

Non-SMC Condensin I Complex Subunit H

Function

Regulatory subunit of the condensin complex, a complex required for conversion of interphase chromatin into mitotic-like condense chromosomes. The condensin complex probably introduces positive supercoils into relaxed DNA in the presence of type I topoisomerases and converts nicked DNA into positive knotted forms in the presence of type II topoisomerases (PubMed:11136719).

Early in neurogenesis, may play an essential role to ensure accurate mitotic chromosome condensation in neuron stem cells, ultimately affecting neuron pool and cortex size (PubMed:27737959).

Biological Process

Cell division Source: UniProtKB-KW
Female meiosis chromosome separation Source: Ensembl
Meiotic chromosome condensation Source: Ensembl
Mitotic chromosome condensation Source: UniProtKB
Positive regulation of chromosome condensation Source: ComplexPortal
Positive regulation of chromosome segregation Source: Ensembl
Positive regulation of chromosome separation Source: Ensembl

Cellular Location

Cytoplasm
Nucleus
Other locations
Chromosome
Note: In interphase cells, the majority of the condensin complex is found in the cytoplasm, while a minority of the complex is associated with chromatin. A subpopulation of the complex however remains associated with chromosome foci in interphase cells. During mitosis, most of the condensin complex is associated with the chromatin. At the onset of prophase, the regulatory subunits of the complex are phosphorylated by CDK1, leading to condensin's association with chromosome arms and to chromosome condensation. Dissociation from chromosomes is observed in late telophase.

Involvement in disease

Microcephaly 23, primary, autosomal recessive (MCPH23):
A form of microcephaly, a disease defined as a head circumference more than 3 standard deviations below the age, sex and ethnically matched mean. Brain weight is markedly reduced and the cerebral cortex is disproportionately small.

PTM

Phosphorylated by CDK1. Its phosphorylation, as well as that of NCAPD2 and NCAPG subunits, activates the condensin complex and is required for chromosome condensation (By similarity).