The Physics of Phagocytosis: How Polymerizing Polymers Drive Cell Engulfment of Particles

Event Dates: 

Wednesday, December 2, 2015 - 4:00pm

CTQM Seminar Type: 

  • Related Seminar Series

Speaker Name(s): 

Jennifer Curtis

Speaker Affiliation(s): 

Georgia Institute of Technology

Abstract, Event Details: 

Cell processes have evolved to be extremely robust. According to engineering principles, building a machine with robust function requires modular design and compartmentalization.  This is consistent with the observation that seemingly disparate cell processes like cell motility, phagocytosis and cytokinesis possess common sets of molecules that work together to achieve similar activities within a larger cellular event. For example, all of these processes require actin-driven membrane deformation, the exertion of contractile forces, and exquisite control of membrane tension. 
With this broader perspective in mind, we investigate phagocytosis, the dramatic mechanical process by which individual cells engulf foreign bodies or debris.  It is critical to the immune response, being the hallmark behavior of white blood cells.   Considerable effort has been devoted to elucidating the biochemical pathways that direct phagocytosis.  However, mechanics of phagocytosis has received less attention.  We present a systematic study of mechanical signature of phagocytosis, including the forces and dynamics that occur during cell engulfment of a substrate, and the reproducibility from one phagocytotic event to another.  Our studies show that the majority of cells behave in a similar manner, having distinct phases of initial-contact, rapid spreading, and late-stage contraction.  Further the engulfment dynamics appear to collapse onto a single ‘master curve’ similar to that found for cell spreading in other unrelated scenarios. Our studies provide new territory for gathering details about the ‘modular’ actomyosin machinery that regulates phagocytosis and other cell mechanical processes.  In addition to addressing a long-standing puzzle about actin architecture in phagocytosis, we expect that our observations will provide insights into systems dependent on the actomyosin molecular machinery and chemo-mechanical coupling.