Abstract
The actin cytoskeleton participates in a range of cellular processes. It supports cell shape changes by propagating forces within cells and between cells and their environment. Terminal cells of the Drosophila respiratory system form a subcellular tube by invaginating their apical plasma membrane; cortical actin networks at the basal and apical plasma membranes are critical for proper morphogenesis. Basal actin affects apical membrane morphogenesis, and it is not known how the two separate actin pools communicate. We report here that actin assembles around vesicles of the late endocytic pathway, which are present in the growth cone of the cell, between the tip of the subcellular tube and the leading filopodia of the basal membrane. Actin organized at late endosomes extends towards both membrane compartments. Preventing proper actin nucleation at late endosomes disturbs the directionality of tube growth, uncoupling it from the direction of cell elongation. Severing actin in this area affects tube integrity. These findings demonstrate a role for the late endocytic pathway in organizing actin for proper cell morphogenesis, in addition to its known role in membrane and protein trafficking.
Competing Interest Statement
The authors have declared no competing interest.
