Apoptotic and Nonapoptotic Cell Death in Caenorhabditis elegans Development

Programmed cell death (PCD) is an essential component of animal development, and aberrant cell death underlies many disorders. Understanding mechanisms that govern PCD during development can provide insight into cell death programs that are disrupted in disease. Key steps mediating apoptosis, a highly conserved cell death program employing caspase proteases, were first uncovered in the nematode Caenorhabditis elegans , a powerful model system for PCD research. Recent studies in C. elegans also unearthed conserved nonapoptotic caspase-independent cell death programs that function during development. Here, we discuss recent advances in understanding cell death during C. elegans development. We review insights expanding the molecular palette behind the execution of apoptotic and nonapoptotic cell death, as well as new discoveries revealing the mechanistic underpinnings of dying cell engulfment and clearance. A number of open questions are also discussed that will continue to propel the field over the coming years.