ARPC1B Gene

The ARPC1B gene (ARPC1B stands for "Actin Related Protein 2/3 Complex Subunit 1B") is a protein coding gene located on chromosome 7q22.1.

The ARPC1B gene encodes one of the seven subunits of the human Arp2/3 protein complex. This subunit belongs to the SOP2 family of proteins. It is likely that a second protein encoded by the ARPC1A gene functions with it as the p41 subunit of the human Arp2/3 complex, a multiprotein complex that mediates actin polymerization after stimulation by nucleation-promoting factor (NPF). It is likely that the complex also plays a role in centrosomal homeostasis, being an activator and substrate of Aurora A kinase.

In addition to its role in the cytoplasmic cytoskeleton, the Arp2/3 complex also promotes actin polymerization in the nucleus, regulating gene transcription and repair of damaged DNA. The Arp2/3 complex promotes homologous recombination (HR) repair in response to DNA damage by promoting actin polymerization in the nucleus to drive the mobility of double-strand breaks (DSBs).

Diseases associated with ARPC1B include.

• Immunodeficiency 71 with inflammatory manifestations, congenital thrombocytopenia, and combined T- and B-cell immunodeficiency (Immunodeficiency 71 with inflammatory disease and congenital thrombocytopenia, OMIM: 617718).

Associated pathways include immune response, CCR3 signaling in eosinophils, and EPH-ephrin signaling.

1. Brigida I et al (2018) T-cell defects in patients with ARPC1B germline mutations account for combined immunodeficiency. Blood 132: 2362-2374.
2. Kahr WH et al. (2017) Loss of the Arp2/3 complex component ARPC1B causes platelet abnormalities and predisposes to inflammatory disease. Nature Commun. 8: 14816
3. Kuijpers TW et al (2017) Combined immunodeficiency with severe inflammation and allergy caused by ARPC1B deficiency. J Allergy Clin Immun 140: 273-277.
4. Papadatou I et al (2021) A Novel Synonymous ARPC1B Gene Mutation Causes a Syndrome of Combined Immunodeficiency, Asthma, and Allergy With Significant Intrafamilial Clinical Heterogeneity. Front Immunol12:634313.
5. Thaventhiran JED et al (2020) Whole-genome sequencing of a sporadic primary immunodeficiency cohort. Nature 583: 90-95.