Calcium-binding protein 39 is a protein that in humans is encoded by the CAB39 gene.
The protein encoded by this gene associates with STK11 (<u>S</u>erine/<u>T</u>hreonine <u>K</u>inase <u>11</u>) and STRAD (<u>ST</u>E20-<u>R</u>elated <u>AD</u>aptor protein). CAB39 enhances formation of STK11/STRAD complexes and stimulates STK11 catalytic activity. CAB39 may function as a scaffolding component of the STK11/STRAD complex and regulates STK11 activity and cellular localization.