Rab (G-protein)

[2] Rab proteins generally possess a GTPase fold, which consists of a six-stranded beta sheet which is flanked by five alpha helices.

A guanine nucleotide exchange factor (GEF) catalyzes the conversion from GDP-bound to GTP-bound form, thereby activating the Rab.

[7] Mutations in the GDI1 gene, which encodes a guanosine nucleotide dissociation inhibitor, have been shown to lead to X-linked nonspecific intellectual disability.

In a study done on mice, carriers for a deletion of the GDI1 gene have shown marked abnormalities in short-term memory formation and social interaction patterns.

It is noted that the social and behavioral patterns exhibited in mice that are carriers of the GDI1 protein are similar to those observed in humans with the same deletion.

The loss of the GDI1 gene has been shown through brain extracts of the mutant mice to lead to the accumulation of the Rab4 and Rab5 proteins, thus inhibiting their function.

In addition to directly causing cancer, dysregulation of Rab proteins has also been linked to progression of already existent tumors, and contributing to their malignancy.