On April 20th, Cell published a report from ION entitled “Long-Range Ca2+ Signaling from Growth Cone to Soma Mediates Reversal of Neuronal Migration Induced by Slit-2”. This work was done mainly by two graduate students Chen-bin Guan and Hua-tai Xu, under the supervision of Drs. Mu-ming Poo and Xiao-bing Yuan.

Migrating neurons are highly polarized and exhibit coordinated translocation of their cell body and the growth cone of their leading neurites. The current study showed that the leading growth cone of migrating cerebellar granule cells is responsible for sensing the extracellular repulsive guidance signal Slit2. In response to Slit2, a cytoplasmic Ca2+ wave propagates from the growth cone to the cell body and this Ca2+ wave is both necessary and by itself sufficient for Slit2-induced reversal of neuronal migration. Furthermore, the reversal of migration requires the activity of the small GTPase RhoA and is accompanied by a front-to-rear redistribution of the RhoA activity.

Many neurological disorders are associated with defects in neuronal migration during development. Studies of the fundamental mechanisms of neuronal migration will help our understanding the etiology of these diseases.