Filopodia act as phagocytic tentacles and pull with discrete steps and a load-dependent velocity

Title data

Kress, Holger ; Stelzer, Ernst H. K. ; Holzer, Daniela ; Buss, Folma ; Griffiths, Gareth ; Rohrbach, Alexander:
Filopodia act as phagocytic tentacles and pull with discrete steps and a load-dependent velocity.
In: Proceedings of the National Academy of Sciences of the United States of America. Vol. 104 (2007) Issue 28 . - pp. 11633-11638.
ISSN 1091-6490
DOI: https://doi.org/10.1073/pnas.0702449104

Official URL:

Abstract in another language

Filopodia are thin, spike-like cell surface protrusions containing bundles of parallel actin filaments. So far, filopodial dynamics has mainly been studied in the context of cell motility on coverslip-adherent filopodia by using fluorescence and differential interference contrast (DIC) microscopy. In this study, we used an optical trap and interferometric particle tracking with nanometer precision to measure the three-dimensional dynamics of macrophage filopodia, which were not attached to flat surfaces. We found that filopodia act as cellular tentacles: a few seconds after binding to a particle, filopodia retract and pull the bound particle toward the cell. We observed F-actin-dependent stepwise retraction of filopodia with a mean step size of 36 nm, suggesting molecular motor activity during filopodial pulling. Remarkably, this intracellular stepping motion, which was measured at counteracting forces of up to 19 pN, was transmitted to the extracellular tracked particle via the filopodial F-actin bundle and the cell membrane. The pulling velocity depended strongly on the counteracting force and ranged between 600 nm/s at forces <1 pN and ≈40 nm/s at forces >15 pN. This result provides an explanation of the significant differences in filopodial retraction velocities previously reported in the literature. The measured filopodial retraction force–velocity relationship is in agreement with a model for force-dependent multiple motor kinetics.

Further data

Item Type:	Article in a journal
Refereed:	No
Additional notes:	Named by Discover Magazine as one of the "Top 100 Science Stories of 2007"
Institutions of the University:	Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Professor Experimental Physics VI - Biologial Physics > Professor Experimental Physics VI - Biologial Physics - Univ.-Prof. Dr. Holger Kreß Faculties Faculties > Faculty of Mathematics, Physics und Computer Science Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics Faculties > Faculty of Mathematics, Physics und Computer Science > Department of Physics > Professor Experimental Physics VI - Biologial Physics
Result of work at the UBT:	No
DDC Subjects:	500 Science > 530 Physics 500 Science > 570 Life sciences, biology
Date Deposited:	26 Feb 2021 09:02
Last Modified:	05 Sep 2022 07:37
URI:	https://eref.uni-bayreuth.de/id/eprint/63439