Inhibitor of the cyclin-dependent kinase CDC28. Necessary for cell cycle arrest. Involved in pheromone response. Contributes to mating efficiency. Required for oriented polarization of yeast cells in response to mating pheromones. Associates with the CDC28-CLN complex. By alpha-factor in a cells. There is evidence to suggest that the N-terminal part may be sufficient for cell cycle arrest and the C-terminal may be necessary for some step in mating. Thought to be phosphorylated by MAP kinase FUS3. Thought to enhance the binding of FAR1 to G1-specific cyclin-dependent kinase (CDK) complexes. Some mutants appear to be defective in mating because they are unable to locate the mating partner. Present with 238 molecules/cell in log phase SD medium.