Active Composite Cell Surface – local control of clustering and sorting
Madan Rao (Raman Research Institute & National Centre for Biological Sciences-TIFR, Bangalore)
The surface of a living cell needs to regulate and control its local composition in a variety of contexts such as endocytosis and signalling. We have shown that many cell surface molecules are organised at multiple scales by their coupling to a thin cortical actomyosin layer, which actively drives local cell membrane composition and shape. This includes both transmembrane proteins and lipid anchored proteins, such as GPI-anchored proteins. Crucial to this engagement is the spontaneous emergence of localized contractile platforms in the 2dim active cortical fluid. Both the nanoscale clustering and the mesoscale segregation display the unique signatures of activity. We have recently recapitulated many of these effects in a minimal reconstituted system. I will end by discussing potential implications of this active composite cell surface for the processing of cellular information.