title: CK1 activates minus-end-directed transport of membrane organelles along microtubules.
abstract: Microtubule (MT)-based organelle transport is driven by MT motor proteins that move cargoes toward MT minus-ends clustered in the cell center (dyneins) or plus-ends extended to the periphery (kinesins). Cells are able to rapidly switch the direction of transport in response to external cues, but the signaling events that control switching remain poorly understood. Here, we examined the signaling mechanism responsible for the rapid activation of dynein-dependent MT minus-end-directed pigment granule movement in Xenopus melanophores (pigment aggregation). We found that, along with the previously identified protein phosphatase 2A (PP2A), pigment aggregation signaling also involved casein kinase 1ε (CK1ε), that both enzymes were bound to pigment granules, and that their activities were increased during pigment aggregation. Furthermore we found that CK1ε functioned downstream of PP2A in the pigment aggregation signaling pathway. Finally, we discovered that stimulation of pigment aggregation increased phosphorylation of dynein intermediate chain (DIC) and that this increase was partially suppressed by CK1ε inhibition. We propose that signal transduction during pigment aggregation involves successive activation of PP2A and CK1ε and CK1ε-dependent phosphorylation of DIC, which stimulates dynein motor activity and increases minus-end-directed runs of pigment granules.
authors.affiliation: Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA.
authors.forename: Kazuho
authors.initials: K
authors.lastname: Ikeda
authors.forename: Olga
authors.initials: O
authors.lastname: Zhapparova
authors.forename: Ilya
authors.initials: I
authors.lastname: Brodsky
authors.forename: Irina
authors.initials: I
authors.lastname: Semenova
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Tirnauer
authors.forename: Ilya
authors.initials: I
authors.lastname: Zaliapin
authors.forename: Vladimir
authors.initials: V
authors.lastname: Rodionov
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000502:physiology*; D047389:Casein Kinase I / Q000037:antagonists & inhibitors / Q000378:metabolism; D018929:Cell Culture Techniques; D003594:Cytoplasmic Granules / Q000378:metabolism; D004398:Dyneins / Q000378:metabolism*; D016547:Kinesins / Q000378:metabolism*; D008547:Melanophores / Q000166:cytology / Q000201:enzymology; D008870:Microtubules / Q000378:metabolism; D009068:Movement / Q000502:physiology; D015388:Organelles / Q000378:metabolism*; D010766:Phosphorylation; D010860:Pigments, Biological / Q000378:metabolism*; D011485:Protein Binding; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D054648:Protein Phosphatase 2 / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D014982:Xenopus laevis / Q000502:physiology
chemical_list: D010860:Pigments, Biological; D047428:Protein Kinase Inhibitors; D047389:Casein Kinase I; D054648:Protein Phosphatase 2; D004398:Dyneins; D016547:Kinesins