Abstract: In Saccharomyces cerevisiae the protein kinase Cbk1p is a member of the RAM network that is involved in cell separation after cytokinesis, cell integrity and cell polarity. In cell separation, the RAM network promotes the daughter cell specific localization of the transcription factor Ace2p, resulting in the asymmetric transcription of genes whose products are necessary to digest the septum joining the mother and daughter cell. RAM and SSD1 play a role in the maintenance of cell integrity. In the presence of a wild type SSD1 gene, deletion of any RAM component causes cell lysis. We show here that some mutations of CBK1 also lead to a reduced fertility and a reduced expression of some of the mating type specific genes. As polarized growth is an integral part of the mating process we have isolated suppressors of the fertility defect. Amongst these, mutations in BRR1 or MPT5 lead to a restoration of fertility and a more-or-less pronounced restoration of polarity; they also show genetic interactions with SSD1. Our experiments reveal a multilayered system controlling aspects of cell separation, cell integrity, mating and polarized growth.