Related Experiment Video
Updated: May 24, 2026

Using Microfluidics and Fluorescence Microscopy to Study the Assembly Dynamics of Single Actin Filaments and Bundles
Published on: May 5, 2022
Actin filament elasticity and retrograde flow shape the force-velocity relation of motile cells
Juliane Zimmermann1, Claudia Brunner, Mihaela Enculescu
1Mathematical Cell Physiology, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany. juliane.zimmermann@mdc-berlin.de
Abstract:
Cells migrate through a crowded environment during processes such as metastasis or wound healing, and must generate and withstand substantial forces. The cellular motility responses to environmental forces are represented by their force-velocity relation, which has been measured for fish keratocytes but remains unexplained. Even pN opposing forces slow down lamellipodium motion by three orders of magnitude. At larger opposing forces, the retrograde flow of the actin network accelerates until it compensates for polymerization, and cell motion stalls. Subsequently, the lamellipodium adapts to the stalled state. We present a mechanism quantitatively explaining the cell's force-velocity relation and its changes upon application of drugs that hinder actin polymerization or actomyosin-based contractility. Elastic properties of filaments, close to the lamellipodium leading edge, and retrograde flow shape the force-velocity relation. To our knowledge, our results shed new light on how these migratory responses are regulated, and on the mechanics and structure of the lamellipodium.
Related Concept Videos
Actin Polymerization and Cell Motility
Actin cytoskeleton dynamics can produce pushing, pulling, and resistance forces that help the cell to migrate.
The Role of Actin and Myosin in Non-muscle Cells
Role of Myosin in Cell Migration
Myosin II is a hexamer comprising two heavy chains with globular heads and coiled-coil tails, two regulatory light chains, and two essential light chains. The ATPase sites on the myosin heads hydrolyze ATP, and the released phosphate generates the force for contraction. It is...
Adaptability of Cytoskeletal Filaments
Mechanism of Filopodia Formation
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
Mechanism of Lamellipodia Formation

