Related Experiment Video
Updated: May 18, 2026

"Phagosome Closure Assay" to Visualize Phagosome Formation in Three Dimensions Using Total Internal Reflection Fluorescent Microscopy (TIRFM)
Published on: August 26, 2016
The motor protein myosin 1G functions in FcγR-mediated phagocytosis
Anna E Dart1, Sylvain Tollis, Michael D Bright
1Division of Molecular Biosciences, Imperial College, London SW7 2AZ, UK.
Abstract:
Phagocytosis is the force-dependent complex cellular process by which immune cells engulf particles. Although there has been considerable progress in understanding ligand-receptor-induced actin polymerisation in pushing the membrane around the particle, significantly less is known about how localised contractile activities regulate cup closure in coordination with the actin cytoskeleton. Herein, we show that the unconventional class-I myosin, myosin 1G (Myo1G) is localised at phagocytic cups following Fcγ-receptor (FcγR) ligation in macrophages. This progressive recruitment is dependent on the activity of phosphoinositide 3-kinase and is particularly important for engulfment of large particles. Furthermore, point mutations in the conserved pleckstrin homology-like domain of Myo1G abolishes the localisation of the motor protein at phagocytic cups and inhibits engulfment downstream of FcγR. Binding of Myo1G to both F-actin and phospholipids might enable cells to transport phospholipids towards the leading edge of cups and to facilitate localised contraction for cup closure.
Related Concept Videos
Overview of Myosin Structure and Function
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...
Phagocytosis
Phagocytosis
The objective of phagocytosis is often destruction. Cells use phagocytosis to eliminate unwelcome visitors, like pathogens (e.g., viruses and bacteria). Many immune system cells, including...
The Role of Actin and Myosin in Non-muscle Cells
Microtubule Associated Motor Proteins

