Speaker: Prof. Satyajit Mayor. Leverhulme International Professor, Centre for Mechanochemical Cell Biology

 

Host: Prof. Ulrike Eggert

 

Title: Encoding mechanical information in the ATP-fuelled membrane of a living cell

 

Abstract: A eukaryotic cell interfaces with the external milieu constantly decoding signals in the form of chemical and mechanical inputs and responding to it almost instantly. These cues are interpreted by membrane receptors embedded in the plasma membrane. Compelling evidence from numerous studies including our own¹, indicate that the plasma membrane is involved in encoding, amplifying and providing feedback for these extracellular signals. How can a fluid bilayer with the kind of compositional heterogeneity that exists in the plasma membrane, carry out such information processing tasks? By studying the impact of integrin receptor activation on membrane organization, the cell appears to create localized mesoscale liquid-ordered (lo) membrane domains (termed active emulsions)² downstream of RhoA-signalling and mechano-transduction. These membrane domains encode information about the chemical and mechanical nature of the substrate, regulating crucial aspects of integrin receptor function, including cell spreading and migration. This level of regulated organization in a fluid membrane bilayer is only possible due to its engagement with a medley of myosin proteins at or near the plasma membrane, draped over a dynamic cortical actin meshwork, and an actively maintained membrane bilayer asymmetry. This ATP-fuelled actin-membrane composite thus behaves as a mechano-responsive medium, serving to integrate chemical and physical cues presented at the cell periphery for the regulation of cell physiology.