Kinesin adapter JLP links PIKfyve to microtubule-based endosome-to-trans-Golgi network traffic of furin.

摘要: JIPs (c-Jun N-terminal kinase interacting proteins), which scaffold JNK/p38 MAP signaling modules, also bind conventional kinesins and are implicated in microtubule-based membrane trafficking neuronal cells. Here we have identified a novel splice variant of the Jip4 gene product JLPL (JNK-interacting leucine zipper protein) yeast-two hybrid screens with phosphoinositide PIKfyve. The interaction was confirmed by pulldown coimmunoprecipitation assays native It engages PIKfyve cpn60_TCP1 consensus sequence last 75 residues JLP C terminus. Subpopulations both proteins cofractionated populated similar structures at cell perinuclear region. Because is essential endosome-to-trans-Golgi network (TGN) cargo transport, tested whether functional partner this pathway. Short interfering RNA (siRNA)-mediated depletion endogenous or profoundly delayed transport chimeric furin (Tac-furin) from endosomes to TGN CHO line, rescued upon ectopic expression siRNA-resistant constructs. Peptides contact sites JLP, dominant-negative mutant introduced into cells microinjection, induced defect. Tac-TGN38 delivery TGN, unlike that Tac-furin, does not require intact microtubules, monitored effect peptides administration on trafficking. Remarkably, neither maneuver altered TGN. Our data indicate interacts their association required microtubule-based, but microtubule-independent, endosome-to-TGN transport.