A minimal system to establish microtubule-based cell polarity in vitro

In this thesis we took the challenge to in vitro reconstitute a minimal phenomenon essential for live: Cell polarity. This is an ubiquitous phenomenon that allows cells to define a direction for migration, growth or division. Our study focussed on microtubulebased establishment of polarity taking S. pombe as a model organism. In this rod-shaped unicellular organism, microtubules deposit polarity factor proteins to the poles of the cell, leaving only there cues for initiating the cascade for cellular growth. Such pattern formation is very robust and is believed to rely on feedback mechanisms. In our study, we hypothesized what would be the minimum components needed for the establishment of a polarized cortical pattern of proteins and developed an in vitro system that fulfils those requirements. Those where:
• Microtubule-based transport of polarity factors.
• Elongated cell shape.
• Cortical receptor for the polarity factors.