GBP binds kinesin light chain and translocates during cortical rotation in Xenopus eggs

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TitleGBP binds kinesin light chain and translocates during cortical rotation in Xenopus eggs
Publication TypeJournal Article
Year of Publication2003
AuthorsWeaver C, Farr GH, Pan WJ, Rowning BA, Wang JY, Mao JH, Wu DQ, Li L, Larabell CA, Kimelman D
Journal TitleDevelopment
Journal DateNov
ISBN Number0950-1991
Accession NumberISI:000187399800013
Keywordsaxis specification, axis-inducing activity, axonal-transport, beta-catenin, cell-cycle, cortical rotation, embryonic axis, frat, glycogen-synthase kinase-3, i-epsilon, microtubules, signaling pathway, ventral axis, wnt pathway

In Xenopus, axis development is initiated by dorsally elevated levels of cytoplasmic beta-catenin, an intracellular factor regulated by GSK3 kinase activity. Upon fertilization, factors that increase beta-catenin stability are translocated to the prospective dorsal side of the embryo in a microtubule-dependent process. However, neither the identity of these factors nor the mechanism of their movement is understood. Here, we show that the GSK3 inhibitory protein GBP/Frat binds kinesin light chain (KLC), a component of the microtubule motor kinesin. Upon egg activation, GBP-GFP and KLC-GFP form particles and exhibit directed translocation. KLC, through a previously uncharacterized conserved domain, binds a region of GBP that is required for GBP translocation and for GSK3 binding, and competes with GSK3 for GBP. We propose a model in which conventional kinesin transports a GBP-containing complex to the future dorsal side, where GBP dissociates and contributes to the local stabilization of beta-catenin by binding and inhibiting GSK3.

URL<Go to ISI>://000187399800013