APS March Meeting 2014
Volume 59, Number 1
Monday–Friday, March 3–7, 2014;
Denver, Colorado
Session S3: Focus Session: Intracellular Organization
8:00 AM–11:00 AM,
Thursday, March 6, 2014
Room: 107
Sponsoring
Unit:
DBIO
Chair: Margaret Gardel, The University of Chicago
Abstract ID: BAPS.2014.MAR.S3.4
Abstract: S3.00004 : Membrane tension regulates clathrin-coated pit dynamics
8:36 AM–9:12 AM
Preview Abstract
Abstract
Author:
Allen Liu
(University of Michigan)
Intracellular organization depends on close
communication between the extracellular environment and a network of
cytoskeleton filaments. The interactions between cytoskeletal filaments and
the plasma membrane lead to changes in membrane tension that in turns help
regulate biological processes. Endocytosis is thought to be stimulated by
low membrane tension and the removal of membrane increases membrane tension.
While it is appreciated that the opposing effects of exocytosis and
endocytosis have on keeping plasma membrane tension to a set point, it is
not clear how membrane tension affects the dynamics of clathrin-coated pits
(CCPs), the individual functional units of clathrin-mediated endocytosis.
Furthermore, although it was recently shown that actin dynamics counteracts
membrane tension during CCP formation, it is not clear what roles plasma
membrane tension plays during CCP initiation. Based on the notion that
plasma membrane tension is increased when the membrane area increases during
cell spreading, we designed micro-patterned surfaces of different sizes to
control the cell spreading sizes. Total internal reflection fluorescence
microscopy of living cells and high content image analysis were used to
quantify the dynamics of CCPs. We found that there is an increased
proportion of CCPs with short (\textless 20s) lifetime for cells on larger
patterns. Interestingly, cells on larger patterns have higher CCP initiation
density, an effect unexpected based on the conventional view of decreasing
endocytosis with increasing membrane tension. Furthermore, by analyzing the
intensity profiles of CCPs that were longer-lived, we found CCP intensity
decreases with increasing cell size, indicating that the CCPs are smaller
with increasing membrane tension. Finally, disruption of actin dynamics
significantly increased the number of short-lived CCPs, but also decreased
CCP initiation rate. Together, our study reveals new mechanistic insights
into how plasma membrane tension regulates the dynamics of CCPs.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2014.MAR.S3.4