Apoptosis and the yeast actin cytoskeleton.

Actin represents one of the most abundant and extensively studied proteins found in eukaryotic cells. It has been identified as a major target for destruction during the process of apoptosis. Recent research has also highlighted a role for cytoskeletal components in the initiation and inhibition of apoptotic processes. The high degree of conservation that exists between actins from divergent eukaryotes, particularly with respect to those that contribute to the cytoskeleton, has meant that functional studies from the model yeast Saccharomyces cerevisiae have proven useful in elucidating its cellular roles. Within the context of apoptosis in yeasts, actin seems to function as part of the signalling mechanisms that link nutritional sensing to a mitochondrial-dependent commitment to cell death. Studies in yeasts have also shown that oxidative damage accrued by the actin cytoskeleton is closely monitored and is tethered to an apoptotic response. Strong, but as yet, undefined links between the actin cytoskeleton and apoptosis have also been described in studies from plant and animal systems. The widespread involvement of actin in apoptotic mechanisms from diverse eukaryotic organisms raises the possibility of conserved regulatory pathways, further strengthening the relevance of yeast research in this area.