Signaling, Actin Dynamics and Endocytosis

Endocytosis is an essential process for normal function of all living cells. Cells get nutrients, and control the surface-expressional level of proteins as well as membrane hemostats through the endocytosis. Endocytosis process is regulated in response to functional status of a particular cell. Signaling events and the endocytosis process go hand in hand to fulfill cellular functions. Although our understanding of the endocytosis process has grown rapidly during the last decade, little is known about how it is interconnected functionally with the signaling status of cells. During endocytosis, vesicles are formed from the plasma membrane through complex molecular machinery. The location where the vesicles are formed is rich in cortical actin cytoskeleton that supports the plasma membrane. To enter cells, vesicles have to diffuse through the cortical actin cytoskeleton. The actin cytoskeleton has a very dynamic structure and actively participates a wide variety of cellular functions. In addition to its central role in cytokinesis, cell shape, cell motility, and cell polarity, a connection between the endocytosis process and the actin cytoskeleton has been implicated in both yeast and mammalian system. In recent years the knowledge on how the actin cytoskeleton participates in the generation of coordinated cellular responses to external stimuli is grown rapidly. In this review, we focus on the potential roles of the actin cytoskeleton in regulating the endocytosis process in response to signaling events.