Tuning the Mechanics of Cell Adhesion

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Date/Time:Monday, 23 Sep 2013 from 4:10 pm to 5:00 pm
Location:Physics 0003
Phone:515-294-5441
Channel:Colloquium
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Sanjeevi Sivasankar (Iowa State University)

The establishment and maintenance of boundaries and compartments between cell populations is essential for multicellular life. This process occurs reliably despite constant mechanical perturbations. For instance, during embryonic development and in wound healing, cells tug on each other as they rearrange and migrate. Similarly, mature tissue like the skin and muscle are exposed to continuous mechanical assault from their external environment. How cell populations maintain their integrity in the presence of mechanical stress is not understood at the molecular level.

Cadherins are family of cell-adhesion proteins that play a key role in this process. Their principle function is to bind cells together and resist mechanical force. Here we use single molecule force measurements and computer simulations to identify how cadherins modulate their adhesion in response to mechanical stress. We show that cadherins form three types of adhesive bonds: catch bonds which, counter-intuitively, become longer lived and lock in the presence of tensile force, slip bonds which become shorter lived when pulled and ideal bonds which are insensitive to tugging. In response to mechanical stimuli, cadherins alter their conformation and switch their adhesive properties. It is likely that catch, slip and ideal bonds serve as a general mechanism that adhesive proteins use to withstand tensile force and tune the mechanical properties of intercellular junctions.