Organization of actin microfilaments in the apical border of oviduct ciliated cells

Abstract

Actin microfilaments were localized in quail oviduct ciliated cells using decoration with myosin subfragment S1 and immunogold labeling. These polarized epithelial cells show a well developed cytoskeleton due to the presence of numerous cilia and microvilli at their apical pole. Most S1-decorated microfilaments extend from the microvilli downward towards the upper part of the ciliary striated rootlets with which they are connected. From the microvillous roots, a few microfilaments connect the proximal part of the basal body or the basal foot associated with the basal body. Microfilament polarity is shown by S1 arrowheads pointing away from the microvillous tip to the cell body. Furthermore, short microfilaments are attached to the plasma membrane at the anchoring sites of basal bodies and run along the basal body. The polarity of these short microfilaments is directed from the basal body anchoring fibers downward to the cytoplasm. At the cell periphery, microfilaments from microvillous roots and ciliary apparatus are connected with those of the circumferential actin belt which is associated with the apical zonula adhaerens. Together with the other cytoskeletal elements, the microfilaments increase ciliary anchorage and could be involved in the coordination of ciliary beating. Moreover, microvilli surrounding the cilia probably modify ciliary beating by offering resistance to cilium bending. The presence of microvilli could explain the fact that mainly the upper part of the cilia appanars to be involved in the axonemal bending in metazoan ciliated cells.

Multiciliated Cells in Animals

“…Actin filaments emanating from the basal foot cap have also been observed in vari-ous species, which is in line with the observation that focal adhesion components localize in the vicinity of the basal foot in Xenopus (Fig. 3) (Reed et al 1984;Sandoz et al 1988;Chailley et al 1989;Antoniades et al 2014). In addition, connecting the basal foot to the cytoskeleton involves z-tubulin in Xenopus MCCs.…”

RhoA regulates actin network dynamics during apical surface emergence in multiciliated epithelial cells

“…MCCs are known to develop complex apical actin structures that are not shared with the neighboring mucus-secreting cells into which they emerge, an attribute observed not only in Xenopus (Park et al, 2006;Sedzinski et al, 2016;Turk et al, 2015; but also in MCCs of the mouse airway and avian oviduct (Chailley et al, 1989;Pan et al, 2007). This actin network is crucial not only for apical emergence in nascent cells (Sedzinski et al, 2016) but also for basal body docking (Park et al, 2008) and basal body planar polarization (Turk et al, 2015;.…”

TheTalpid3gene (KIAA0586) encodes a centrosomal protein that is essential for primary cilia formation

“…Another possible reason why ciliogenesis fails in the talpid 3 chicken mutant is because Talpid3 is required for apical actin enrichment. In oviduct ciliated cells, the apical actin network is closely associated with basal body appendages (Chailley et al, 1989), and recent work on Xenopus laevis epidermal cells with motile cilia has shown that apical enrichment of actin is required for ciliogenesis (Park et al, 2006). Therefore, it is possible that the abnormal actin organisation in talpid 3 mutant cells results in basal body misorientation, leading to failure of ciliogenesis.…”