Innexin2 (Inx2) containing vesicles are associated with actin in the sub-basal region of the pupal salivary gland.
Single optical section through a pupal salivary gland cell just below the basal surface. Inx2-containing vesicles (green) resemble putative annular junctions. This region of the cell is rich in F-actin (red, stained here using phalloidin-rhodamine conjugate). Most of the Inx2-positive vesicles are associated with actin fibres (arrows). However, an association is not obvious in all cases (arrowheads). The vesicles indicated by arrowheads may be associated with less-dense strands of actin that are poorly labelled using the phalloidin staining technique. Connexins also interact with the actin cytoskeleton via the intermediary molecule “developmentally regulated brain protein” (drebrin). The identity of the equivalent protein in Drosophila is unknown. A blast search reveals fly gene CG10083 as having the highest homolgy to human drebrin, but the proteins share only 34% identity and most of that is in the F-actin binding region. Almost nothing is known about the role of this protein in Drosophila. Note: the location of arrows and arrowheads is the same in all three panels. Size bar = 5μm.