TY - JOUR
T1 - The force-velocity relationship for the actin-based motility of Listeria monocytogenes
AU - McGrath, James L.
AU - Eungdamrong, Narat J.
AU - Fisher, Charles I.
AU - Peng, Fay
AU - Mahadevan, Lakshminarayanan
AU - Mitchison, Timothy J.
AU - Kuo, Scot C.
N1 - Funding Information:
We thank James Harden, Anthony Beris, and Colin Keary for insightful discussions on drag forces in viscoelastic fluids. We thank Eric Osborn and John Hartwig for material and help with actin polymerization assays. N.J.E., T.J.M., and L.M. were supported by grants from the Center for Biomedical Engineering at M.I.T. and the Edgerly Foundation. J.L.M. and S.C.K. were supported by grants from the National Science Foundation and the Whitaker Foundation. S.C.K. and T.J.M. are supported by grants from the National Institutes of Health.
PY - 2003/2/18
Y1 - 2003/2/18
N2 - The intracellular movement of the bacterial pathogen Listeria monocytogenes has helped identify key molecular constituents of actin-based motility (recent reviews [1-4]). However, biophysical as well as biochemical data are required to understand how these molecules generate the forces that extrude eukaryotic membranes. For molecular motors and for muscle, force-velocity curves have provided key biophysical data to distinguish between mechanistic theories. Here we manipulate and measure the viscoelastic properties of tissue extracts to provide the first force-velocity curve for Listeria monocytogenes. We find that the force-velocity relationship is highly curved, almost biphasic, suggesting a high cooperativity between biochemical catalysis and force generation. Using high-resolution motion tracking in low-noise extracts, we find long trajectories composed exclusively of molecular-sized steps. Robust statistics from these trajectories show a correlation between the duration of steps and macroscopic Listeria speed, but not between average step size and speed. Collectively, our data indicate how the molecular properties of the Listeria polymerization engine regulate speed, and that regulation occurs during molecular-scale pauses.
AB - The intracellular movement of the bacterial pathogen Listeria monocytogenes has helped identify key molecular constituents of actin-based motility (recent reviews [1-4]). However, biophysical as well as biochemical data are required to understand how these molecules generate the forces that extrude eukaryotic membranes. For molecular motors and for muscle, force-velocity curves have provided key biophysical data to distinguish between mechanistic theories. Here we manipulate and measure the viscoelastic properties of tissue extracts to provide the first force-velocity curve for Listeria monocytogenes. We find that the force-velocity relationship is highly curved, almost biphasic, suggesting a high cooperativity between biochemical catalysis and force generation. Using high-resolution motion tracking in low-noise extracts, we find long trajectories composed exclusively of molecular-sized steps. Robust statistics from these trajectories show a correlation between the duration of steps and macroscopic Listeria speed, but not between average step size and speed. Collectively, our data indicate how the molecular properties of the Listeria polymerization engine regulate speed, and that regulation occurs during molecular-scale pauses.
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U2 - 10.1016/S0960-9822(03)00051-4
DO - 10.1016/S0960-9822(03)00051-4
M3 - Article
C2 - 12593799
AN - SCOPUS:0242684547
VL - 13
SP - 329
EP - 332
JO - Current Biology
JF - Current Biology
SN - 0960-9822
IS - 4
ER -