The Actomyosin Cortex of Cells: A Thin Film of Active Matter

Abstract

The actomyosin cortex is a thin film, containing actin filaments
and myosin molecular motors, located beneath the plasma-membrane of
eukaryotic cells. Active processes, driven by ATP hydrolysis, can generate
mechanical forces in the cortex. Coordinated force-generation drives
large-scale mechanical flows and orientation patterns. These flows can
pattern proteins coupled to the cortex leading to the emergence of
active mechanochemical patterns. In this review, we discuss physical
approaches to understand force-generation and the concomitant patterns
observed in the actomyosin cortex. We briefly outline the hydrodynamic
theory of active gels as applicable to the cortex and discuss
its consequences. We speculate on the role of the actomyosin cortex in
sculpting large-scale tissues and end with an outlook for open problems.