During cytokinesis, the central spindle microtubules and the actomysin contractile ring drive dramatic cell shape changes. These shape changes also involve a rapid increase in the plasma membrane surface area, but how is this achieved? Dyer and colleagues propose that the endosomal trafficking component ARF6 promotes rapid membrane addition during spermatocyte cytokinesis in Drosophila (see ). The researchers show that cytokinesis fails in most meiotic divisions in arf6-null spermatocytes. They use time-lapse microscopy to show that the rapid addition of membrane to the plasma membrane is defective in these spermatocytes and causes furrow regression. In normal spermatocytes, they report, ARF6 is enriched on recycling endosomes at the central spindle and binds to the centralspindlin component Pavarotti. However,ARF6 is not required for central spindle or actomysin contractile ring assembly or for targeting of recycling endosomes to the spindle. They propose,therefore, that ARF6 promotes the rapid recycling of endosomal membrane stores during cytokinesis, thus coordinating membrane recycling with central spindle formation.
