RdgB proteins: functions in lipid homeostasis and signal transduction.
The RdgBs are a group of evolutionarily conserved molecules that contain a phosphatidylinositol transfer protein (PITP) domain. However in contrast to classical PITPs (PITPalpha) with whom they share the conserved PITP domain, these proteins also contain several additional sequence elements whose functional significance remains unknown. The founding member of the family DrdgB alpha (Drosophila rdgB) appears to be essential for sensory transduction and maintenance of ultra structure in photoreceptors (retinal sensory neurons). Although proposed to support the maintenance of phosphatidylinositol 4, 5 bisphosphate [PI (4, 5) P(2)] levels during G-protein coupled phospholipase C activity in these cells, the biochemical mechanism of DrdgB alpha function remains unresolved. More recently, a mammalian RdgB protein has been implicated in the maintenance of diacylglycerol (DAG) levels and secretory function at Golgi membranes. In this review we discuss existing work on the function of RdgB proteins and set out future challenges in understanding this group of lipid transfer proteins.
Trivedi
Deepti
D
Inositide Laboratory, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK.
Padinjat
Raghu
R
D000818:Animals; D004075:Diglycerides / Q000378:metabolism; D004330:Drosophila / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D005136:Eye Proteins / Q000378:metabolism*; D006706:Homeostasis; D006801:Humans; D050356:Lipid Metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism*; D051379:Mice; D010716:Phosphatidylinositols / Q000378:metabolism; D051966:Phospholipase C gamma / Q000378:metabolism; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000502:physiology*
D004075:Diglycerides; D029721:Drosophila Proteins; D005136:Eye Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C107847:PITPNC1 protein, human; D010716:Phosphatidylinositols; C068848:rdgB protein, Drosophila; D051966:Phospholipase C gamma