?
calponin homology (CH) domain found in the Pak Interactive eXchange factor family Pak Interactive eXchange factor (PIX) proteins are Rho guanine nucleotide exchange factors (GEFs), which activate small GTPases by exchanging bound GDP for free GTP. They act as GEFs for both Cdc42 and Rac1, and have been implicated in cell motility, adhesion, neurite outgrowth, and cell polarity. Vertebrates contain two proteins from the PIX family, alpha-PIX and beta-PIX. Alpha-PIX, also called Rho guanine nucleotide exchange factor 6 (ARHGEF6), is localized in dendritic spines where it regulates spine morphogenesis. It controls dendritic length and spine density in the hippocampus. Mutations in the ARHGEF6 gene cause X-linked intellectual disability in humans. Beta-PIX, also called Rho guanine nucleotide exchange factor 7 (ARHGEF7), plays important roles in regulating neuroendocrine exocytosis, focal adhesion maturation, cell migration, synaptic vesicle localization, and insulin secretion. Both alpha-PIX and beta-PIX contain a single copy of the CH domain at the N-terminus. CH domains are actin filament (F-actin) binding motifs. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",