LKB1, a member of the serine/threonine kinase family, is a tumor suppressor. Physically associates with p53, it regulates specific p53 dependent apoptosis pathways. LKB1 protein is present in both the cytoplasm and nucleus of living cells and translocates to mitochondria during apoptosis. Restoring LKB1 activity into cancer cell lines defective for its expression results in a G1 cell cycle arrest.
