Actin Cytoskeleton and Membrane Interactions: Role in GPCR Function and Organization

Cell signaling networks are generally initiated at the cell membrane and mediated by receptors such as the G proteincoupled receptors (GPCRs). Adjacent to the cell membrane lies a complex network of proteins - the actin cytoskeleton to which several structural and physiological roles have been attributed. An emerging role of the cytoskeleton is to modulate GPCR function and organization, either directly or indirectly. The GPCR-cytoskeleton cross-talk is a complex hierarchical process where each step has its own set of rules and combinations. Due to the inherent complexity involved at each step and the multiple spatio-temporal levels, a complete picture is yet to emerge. In this review article, we provide an overview of actin-membrane interactions and how they modulate GPCR function and organization. In this context, we briefly discuss the structural characterization of actin monomers and filaments together with their interactions with partner proteins, such as the actin binding proteins. The effect of actin interactions on membrane domains is examined that assumes significance in light of membrane modulated effects in GPCR function. We aim to bring together concepts in GPCR signaling and cytoskeletal dynamics towards addressing emerging concepts in GPCR function.