Molecular mechanisms of endo- and exocytosis in the baker's yeast

• Applicants: Professor Dr. Adam Bertl; Professor Dr. Gerhard Thiel
• Subject Area: Cell Biology ; Biophysics
• Term: from 2013 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 249976640

Endo- and exocytosis are imperative in numerous cellular processes in eukaryotes, such as polar growth, cell division, motility or signaling. By fusion of exocytotic vesicles cells deliver secretory cargo, membrane-resident proteins and also membrane to the plasma membrane; the retrogarde transport of these materials is provided by fisson of endocytotic vesicles. Since the electrical properties of a cell membrane are comprised of a selective conductance and a capacitance, the latter being proportional to the membrane surface area, changes in the surface area from fusion and fission of vesicles can be directly monitored by recording of the membrane capacitance. In this way the size of individual exo- and endocytotic vesicles and their kinetics of fusion and fission can be recorded in real time in living cells. After showing that this recording technique is also feasible in yeast protoplasts we will in this proposal combine the detailed genetic and biochemical knowledge on exo-/endocytosis in yeast with high resolution capacitance recordings. The use of the rich library of yeast mutants with defects in distinct proteins in the exo- and endocytotic machinery and the use of well established signals for membrane trafficking like the mating pheromones will make it possible to dissect the complex mechanisms of fusion and fission into well defined molecular steps. Because of the conservation of the molecular machinery the results of this work will have strong implications for the understanding of these processes in mammalian cells.

• DFG Programme: Research Grants