MBI PhD Oral Defense

Time: 3pm
Date: Wednesday, 02 May 2018
Venue: MBI, level 5 meeting rooms

Supervisors:  Prof Hanry Yu (Main supervisor), Prof Michael Sheetz (Co-supervisor)

Characterization of cadherin contraction and its role in cell rigidity sensing

by YANG Yi-An, Hanry Yu Group, Sheetz Group

E-cadherin is a major cell-cell adhesion molecule involved in mechanotransduction at cell-cell contacts in tissues. Since cells respond to rigidity and tension in the tissue through E-cadherin, there must be active processes that test and respond to the mechanical properties of these adhesive contacts. Using sub-micrometer, E-cadherin-coated PDMS pillars, we find that cells generate active contractions between E-cadherin adhesions and, powered by myosin activity, pull pillars to a constant distance irrespective of pillar rigidity over a 19-fold range. These cadherin contractions require non-muscle myosin IIB, tropomyosin 2.1, α-catenin and its reversible binding of vinculin to α-catenin. These cadherin contractions are correlated with mechanosensitive cell behaviors. Without cadherin contractions, cells fail to spread to different areas on soft and rigid surface or maintain monolayer integrity. Thus, we suggest that epithelial cells test and respond to the rigidity of neighboring cells by cadherin contractions.

**Please note the examination following the seminar is closed-door**