The protein encoded by this gene is a member of the Rab family of proteins, which is the largest family within the Ras superfamily of GTPases. This gene product is thought to regulate vesicular transport, together with its specific effectors. Mutations in this gene cause several defects, including actin-based melanosome transport defects and immunodeficiency. Mutations in the human ortholog of this gene are associated with Griscelli syndrome type 2. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2014]