19 exons spanning 136.1 kb genomic DNA.

5.9-6.2 kb mRNA, coding sequence: 3.5-3.6 kb
Alternative splicing of the first 5 exons results in the expression of 5 transcript variants (ARHGAP20-1e, ARHGAP20-1d, ARHGAP20-1ad, ARHGAP20-1be, ARHGAP20-1c).

None.

The amino-terminal region shows significant homology to a pleckstrin homology (PH) domain commonly found in eukaryotic signaling proteins. Adjacent to the PH domain a Ras association (RA) domain is postulated, which is found in proteins involved in GTPase-mediated signaling processes. The central section of the protein contains a RhoGAP domain, which is crucial for the regulation of Rho-like GTPases by Rho GTPase-activating proteins in the course of transmitting diverse intracellular signals.

Predominantly expressed in brain, but transcripts were also detected in peripheral blood lymphocytes.

Cytoplasm

The presence of a RhoGAP domain in combination with PH and RA modules indicates that ARHGAP20 is involved in the regulation of Rho-family GTPases. ARHGAP20 was shown to be activated by Rap1 and to induce inactivation of Rho, resulting in the neurite outgrowth.

Mouse: RarhoGAP (RhoGAP having the RA domain), Arhgap20.
Rat: RahoGAP (RhoGAP having the RA domain), Arhgap20.

Single nucleotide polymorphism 1785T/C (transcript variant ARHGAP20-1ad, AY496263).

None detected.

In the tumour cells of one case of B-cell chronic lymphocytic leukemia, the missense mutation 2995T>G (S999A; transcript variant ARHGAP20-1ad, AY496263) was found.