The cytoskeleton controls the dynamics of plasma membrane proteins and facilitates their endocytosis in plants

Abstract

Plasma membranes (PMs) are highly dynamic structures where lipids and proteins can theoretically diffuse freely. However, reports indicate that PM proteins do not freely diffuse within their planes but are constrained by cytoskeleton networks, though the mechanisms for how the cytoskeleton restricts lateral diffusion of plant PM proteins are unclear. Through single-molecule tracking, we investigated the dynamics of 6 Arabidopsis (Arabidopsis thaliana) PM proteins with diverse structures and found distinctions in sizes and dynamics among these proteins. Moreover, we showed that the cytoskeleton, particularly microtubules, limits the diffusion of PM proteins, including transmembrane and membrane-anchoring proteins. Interestingly, the microfilament skeleton regulates intracellular transport of endocytic cargo. Therefore, these findings indicate that the cytoskeleton controls signal transduction by limiting diffusion of PM proteins in specific membrane compartments and participating in transport of internalized cargo vesicles, thus actively regulating plant signal transduction.