Beaven, R., Bastos, R.N., Spanos, C., Romé, P., Cullen, C.F., Rappsilber, J., Giet, R., Goshima, G., Ohkura, H. (2017). 14-3-3 regulation of Ncd reveals a new mechanism for targeting proteins to the spindle in oocytes.  J. Cell Biol. 216(10): 3029--3039.

FBrf0236847

Research paper

The meiotic spindle is formed without centrosomes in a large volume of oocytes. Local activation of crucial spindle proteins around chromosomes is important for formation and maintenance of a bipolar spindle in oocytes. We found that phosphodocking 14-3-3 proteins stabilize spindle bipolarity in Drosophila melanogaster oocytes. A critical 14-3-3 target is the minus end-directed motor Ncd (human HSET; kinesin-14), which has well-documented roles in stabilizing a bipolar spindle in oocytes. Phospho docking by 14-3-3 inhibits the microtubule binding activity of the nonmotor Ncd tail. Further phosphorylation by Aurora B kinase can release Ncd from this inhibitory effect of 14-3-3. As Aurora B localizes to chromosomes and spindles, 14-3-3 facilitates specific association of Ncd with spindle microtubules by preventing Ncd from binding to nonspindle microtubules in oocytes. Therefore, 14-3-3 translates a spatial cue provided by Aurora B to target Ncd selectively to the spindle within the large volume of oocytes.

PMC5626551 (PMC) (EuropePMC)