The role of the Nir/rdgB protein family in membrane trafficking and cytoskeleton remodeling

The Nir/rdgB family of proteins has been identified in a variety of eukaryotic organisms, ranging from worms to mammals. The Drosophila retinal degeneration B (rdgB), a protein that is required for photoreceptor cell viability and light response, was the first to be identified. It consists an amino-terminal phosphatidylinositol (PI)-transfer domain and was proposed to play an essential role in photoreceptor membrane renewal and biogenesis. The other Nir/rdgB family members are functionally and structurally related to the Drosophila homolog and are implicated in regulation of lipid trafficking, metabolism, and signaling. Recent advances have revealed that Nir/rdgB proteins are also involved in regulation of cytoskeletal elements. Thus, these family members exert a broad spectrum of cellular functions and are involved in multiple cellular processes. The physiological functions of these closely related proteins are described in this review. (C) 2004 Elsevier Inc. All rights reserved.