CLOCK and BMAL1 stabilize and activate RHOA to promote F-actin formation in cancer cells

Cancer: Clocking the triggers for tumor progression Two proteins involved in regulating circadian rhythms may promote cancer tumor growth by changing the internal structures of cells. Circadian clock proteins play key roles in cell division, metabolism, and immune responses. Certain clock proteins are implicated in uncontrolled cell and tumor growth. Yong-xin Ma at Sichuan University in Chengdu, China and co-workers have shown that two clock proteins, CLOCK and BMAL1, regulate the arrangement of F-actin microfilaments in the cytoskeleton of cells. The researchers found that CLOCK and BMAL1 interact with an enzyme that promotes the formation of cellular fibers and regulates cell shape and motility. The overexpression of these clock proteins in cancers increases the levels of this enzyme, which changes F-actin structures inside cells. This promotes cancer cell proliferation, migration, and invasion.