Rab GTPases are regulators of intracellular membrane traffic. The Rab27 subfamily consists of Rab27a and Rab27b. Rab27a has been recently implicated in Griscelli Disease, a disease combining partial albinism with severe immunodeficiency. Rab27a plays a key role in the function of lysosomal-like organelles such as melanosomes in melanocytes and lytic granules in cytotoxic T lymphocytes. Little is known about Rab27b.
Cell and Molecular Biology, Division of Biomedical Sciences, Imperial College School of Medicine, Sir Alexander Fleming Building, London SW7 2AZ, UK. jose.ramalho@ic.ac.uk
