Specifically required for meiosis II (MII). Binds to slp1, an activator of the anapahase promoting complex/cyclcosome (APC/C), and counteracts its function in promoting proteolysis of cdc13. By suppressing the degradation of cdc13 at anaphase I this protein may help maintain a sufficient level of cdc2 kinase activity to complete MII. Interacts with slp1. Preferentially expressed under nitrogen starvation conditions. Expression of the full-length mes1 protein requires the presence of the mei2 protein.