The prenyl-binding protein PrBP/δ: A chaperone participating in intracellular trafficking

Expressed ubiquitously, PrBP/delta functions as chaperone/co-factor in the transport of a subset of prenylated proteins. PrBP/delta features an immunoglobulin-like beta-sandwich fold for lipid binding, and interacts with diverse partners. PrBP/delta binds both C-terminal C15 and C20 prenyl side chains of phototransduction poly-peptides and small GTP-binding (G) proteins of the Ras superfamily. PrBP/delta also interacts with the small GTPases, ARL2 and ARL3, which act as release factors (GDFs) for prenylated cargo. Targeted deletion of the mouse Pde6d gene encoding PrBP/delta resulted in impeded trafficking to the outer segments of GRK1 and cone PDE6 which are predicted to be farnesylated and geranylgeranylated, respectively. Rod and cone transducin trafficking was largely unaffected. These trafficking defects produce progressive cone-rod dystrophy in the Pde6d(-/-) mouse. (C) 2012 Elsevier Ltd. All rights reserved.