Pfister Lab

August 18, 2015 by School of Medicine Webmaster

dy actinMy lab studies how cytoplasmic dynein, a microtubule-based motor is regulated to deliver various membrane bounded organelle cargos to the proper locations. Our current focus is on identifying the mechanism(s) involved in dynein binding to specific organelles, using dynein binding to signaling endosomes that form in response to the addition of neurotrophin to cultured neurons. We found that neurotrophin stimulates phosphorylation of a specific amino acid on the dynein intermediate chain (IC) by ERK kinase (extracellular-signal-regulated kinase, a downstream effector the neurotrophin receptor kinase). Live cell imaging with fluorescent protein-tagged wild type and phospho-mimic mutant ICs expressed in neurons, coupled with biochemical studies on purified endosomes support the hypothesis that phosphorylation increases dynein binding to endosomes, but not binding to a second organelle, mitochondria. Importantly, this phosphorylation does not affect dynein binding to dynactin, a known linker of dynein to many cargos. Our data thus suggests that dynein binding to signaling endosome requires a component in addition to dynactin.