Asymmetric neuroblast divisions producing apoptotic cells require the cytohesin GRP-1 in Caenorhabditis elegans.

Cytohesins are Arf guanine nucleotide exchange factors (GEFs) that regulate membrane trafficking and actin cytoskeletal dynamics. We report here that GRP-1, the sole Caenorhabditis elegans cytohesin, controls the asymmetric divisions of certain neuroblasts that divide to produce a larger neuronal precursor or neuron and a smaller cell fated to die. In the Q neuroblast lineage, loss of GRP-1 led to the production of daughter cells that are more similar in size and to the transformation of the normally apoptotic daughter into its sister, resulting in the production of extra neurons.

The DEP domain-containing protein TOE-2 promotes apoptosis in the Q lineage of C. elegans through two distinct mechanisms.

Neuroblast divisions in the nematode Caenorhabditis elegans often give rise to a larger neuron and a smaller cell that dies. We have previously identified genes that, when mutated, result in neuroblast divisions that generate daughter cells that are more equivalent in size. This effect correlates with the survival of daughter cells that would normally die.

The Arf GAP CNT-2 regulates the apoptotic fate in C. elegans asymmetric neuroblast divisions.

During development, all cells make the decision to live or die. Although the molecular mechanisms that execute the apoptotic program are well defined, less is known about how cells decide whether to live or die. In C.