PgmNr Y3064: Boi1 and Boi2 contribute to Secretory Pathway Polarization.

Authors:
J. Kustermann; Y. Wu; N. Johnsson


Institutes
Ulm University, Ulm, Baden-Württemberg, DE.


Keyword: Signal Transduction

Abstract:

Asymmetric cell division is essential for the generation of cell diversity and forms the basis for rejunvenation during cellular aging. For decades, the model organism Saccharomyces cerevisiae (S. c.) has been studied to elucidate the protein networks that enable asymmetric cell division and connect cell polarity establishment to intracellular transport processes. In our work we decipher a new pathway in which the annilin-related yeast proteins Boi1 and Boi2 link Cdc42, the master regulator of cell polarity establishment in S. c. to exocytosis. Boi1 and Boi2 are scaffold proteins of similar structure and partially redundant functions that both bind Cdc42. BOI1 and BOI2 exhibit synthetic lethality and a knock-down of BOI1 in a BOI2 deletion strain causes a severe accumulation of post-golgi vesicles in the daughter cell. In accordance with this observation, I found physical and genetic interactions between Boi1/2 and members of the vesicle fusion machinery. Furthermore, I provide evidence that Boi1 and Boi2 are on top of an interaction cascade to polarize the fusion of post-golgi vesicles to the tip of the cell.

Accordingly, I propose a model in which Boi1 and Boi2 serve as direct adapters between essential core components of the cell polarity and the vesicle fusion machinery and thereby contribute to the polarization of the secretory pathway.



Yeast Database Genetic Index
1. gene symbol: BOI1; systematic name: YBL085W
2. gene symbol: BOI2; systematic name: YER114C