The skin of a living cell is a mechanoresponsive actin-membrane composite
Pr Satyajit MAYOR
National Centre for Biological Sciences, Tata Institute of Fundamental Research, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
Wednesday, May 15th 2019 - 2 p.m.
- Auditorium, IGBMC
Hosted by Functional genomics and cancer, Angela GIANGRANDE
The plasma membrane of a living cell is the interface between the cell and its external milieu. It serves as a dynamic conduit for information transduction and response. It is composed of membrane lipids and protein in the form of a bilayer. However, unlike an artificial membrane, the living membrane is a highly spatially organized system, where specific components are maintained in configurations or domains, far away from chemical equilibrium. This is effected in part by engagement with cortical acto-myosin. An understanding of the physico-chemical principles behind the generation of these localized domains via the active mechanics of actin filaments and myosin is emerging (1, 2).
We now find that signalling receptors fine-tune membrane organization by regulating the active mechanics of dynamic cortical actin filaments, thereby controlling the creation of localized domains. I will present our current understanding of the molecular machinery that participates in this process from our study of integrin receptor signalling. Integrin receptors engage in ‘inside out’ signalling necessary for calibrating the cells’ response to the external chemical and physical world. Integrin receptors reorganize their immediate membrane milieu by generating a specialized membrane microenvironment necessary for its own function (3), giving rise to the idea that the cell surface may be considered as a mechano-responsive, active actin-membrane composite.
References: 1) Gowrishankar, K., et al. (2012). Active remodeling of cortical actin regulates spatiotemporal organization of cell surface molecules. Cell 149, 1353–1367. 2) Raghupathy, R., , et al. (2015). Transbilayer Lipid Interactions Mediate Nanoclustering of Lipid-Anchored Proteins. Cell 161, 581–594. 3) Kalappurakkal et al. (2019) https://www.biorxiv.org/content/early/2017/12/11/232223, Cell (in press)