LKB1/STK11 Serine/Threonine Kinase

Germline mutations of the LKB1 (STK11) tumor suppressor gene can lead to Peutz-Jeghers syndrome (PJS) and a marked predisposition to cancer. LKB1 encodes a serine/threonine kinase that is inactivated in PJS. The tumor suppressor protein PTEN is a LKB1-interacting protein. Several point mutations in LKB1 are associated with PJS and may disrupt the interaction with PTEN suggesting that the loss of this interaction might contribute to PJS. PTEN and LKB1 are predominantly cytoplasmic and nuclear, respectively, the interaction of the two leads to a cytoplasmic relocalization of LKB1. PTEN is a substrate of the kinase LKB1 in vitro.