Involved in the regulation of cell growth. May stabilize the active CDC2-cyclin B1 complex and thereby contribute to the regulation of the cell cycle and the prevention of uncontrolled cell proliferation. May act as a tumor suppressor. Binds EEF1G, TLK2 and CDK1. Associated with the plasma membrane and with microtubules. Detected in dendritic spines, especially in the postsynaptic density (By similarity). Highly expressed in testis, prostate, spleen, thymus, ovary and brain. Detected at lower levels in heart, placenta, small intestine, colon, liver, kidney, skeletal muscle and pancreas. Not detectable in primary tumors from breast and prostate and in many cancer cell lines. Phosphorylated on serine residues. Hyperphosphorylated by the cAMP-dependent kinase PKA during cell-cycle progression. The disease may be caused by variants affecting the gene represented in this entry. Defects in LZTS1 are found in many types of tumors. Belongs to the LZTS family.