Volume 6 Issue 9, September 2004

Cell duplication requires the coordination of nuclear division with diverse cellular morphogenesis events, such as cell wall growth. A novel checkpoint has been identified in yeast that coordinates these two events. Unexpectedly, the dynein-activating dynactin complex, but not dynein itself, is an essential component of this checkpoint mechanism.

Proteins containing the BIR motif have been implicated as regulators of apoptosis and cell division. Apollon, an exceptionally large BIR-containing protein, inhibits apoptosis by targeting key cell death proteins for destruction by the ubiquitin-proteasome pathway. Now, deletion of apollon in the mouse has revealed a crucial function in cell division.

The hyperplasia suppressor gene HSG, previously characterized for its function in mitochondrial fusion, has now been identified as a novel inhibitor of the Ras signalling pathway during smooth muscle cell proliferation. Because of the critical function of this process in atherosclerotic heart disease, these findings may have important clinical implications.