Date of Award


Document Type

Campus Access Dissertation

Degree Name

Doctor of Philosophy (PhD)


Biology/Molecular, Cellular, and Organismal Biology

First Advisor

Linda S. Huang

Second Advisor

Alexey Veraksa

Third Advisor

Rachel Skvirsky


Sporulation in the budding yeast Saccharomyces cerevisiae is a complex developmental process involving a coordinated series of signaling events. SPS1 encodes a STE20 family serine/threonine kinase of the GCKIII subfamily important for spore formation in S. cerevisiae. 14-3-3 proteins are key regulators of signaling by phosphorylated signaling proteins and are conserved throughout eukaryotes. The S. cerevisiae 14-3-3 proteins are encoded by BMH1 and BMH2. Here, we show that Sps1 is phosphorylated on Threonine12 (T12) within a 14-3-3 consensus binding sequence. We find that Sps1 binds to Bmh1 and Bmh2, and demonstrate that this binding is affected by T12. We see that 14-3-3s are involved in yeast sporulation as bmh1Δ and bmh2Δ mutants each decrease sporulation efficiency. An sps1-T12A non-phosphorylatable mutant displays a sporulation efficiency defect and SPS1 genetically interacts with both BMH1 and BMH2, suggesting that the Sps1/14-3-3 interaction is important for sporulation. We see that Sps1 is localized to the nucleus and that Bmh1 and Bmh2 are seen in both the nucleus and cytoplasm during sporulation. Finally, we have mapped the Sps1 nuclear localization sequence to amino acids 411-415 and show that this sequence is necessary and sufficient for nuclear localization. Taken together, these data indicate that Sps1 and 14-3-3s act together to promote proper sporulation in S. cerevisiae.


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