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 tumor suppressor (By similarity). Binds EEF1G, TLK2 and CDK1. Associated with the plasma membrane and with microtubules (By similarity). Detected in dendritic spines, especially in the postsynaptic density. Highly expressed in brain, in particular in cortex, the CA2 region of the hippocampus, olfactory bulb, striatum and pons. Not detectable in the other tissues tested. Highly expressed in cerebellum in 1 to 3 week old rats. Expression levels before and after are much lower. Expression in total brain increases slightly during development and remains at a constant high level after birth. Phosphorylated on serine residues. Hyperphosphorylated by the cAMP-dependent kinase PKA during cell-cycle progression (By similarity). Belongs to the LZTS family.