CLIPR-59 is a lipid raft-associated protein containing a cytoskeleton-associated protein glycine-rich domain (CAP-Gly) that perturbs microtubule dynamics

Abstract

We recently have identified a new cytoplasmic linker protein (CLIP), CLIPR-59, which is involved in the regulation of early endosome/trans-Golgi network dynamics. In contrast with CLIP-170, CLIPR-59 is not localized to microtubules at steady state but is associated with the trans-Golgi network and the plasma membrane. Here we show that the last 30 amino acids (C30) are sufficient for membrane targeting and that two cysteines in the C30 domain are palmitoylated. We demonstrate that CLIPR-59 is associated with lipid rafts via its C-terminal palmitoylated domain. In vitro experiments suggest that CLIPR-59 and its microtubule-binding domain alone have a better affinity for unpolymerized tubulin or small oligomers than for microtubules. In contrast with the CLIP-170 microtubule-binding domain, the CLIPR-59 microtubule-binding domain diminishes microtubule regrowth after nocodazole washout in vivo, showing that this domain can prevent microtubule polymerization. In contrast with the role of linker between membranes and microtubules that was proposed for CLIP function, CLIPR-59 thus may have an "anti-CLIP" function by preventing microtubule-raft interactions.