Functional analysis of domains of Centaurin B1A in plasma membrane remodeling in cellularization in Drosophila embryogenesis

Abstract

Bin-Amphiphysin-Rvs (BAR) domain-containing proteins are known to play key roles in various cellular membrane remodeling processes. These proteins, using their membrane pliable properties and with the aid of multiple auxiliary domains, function to mediate and regulate vesicular trafficking with cytoskeletal dynamics. Centaurin B1A (CenB1A) is a multi-domain protein containing a BAR domain, PH domain, Arf GAP domain, and Ankyrin repeats. Ongoing studies in the lab reveal that loss of CenB1A leads to reduced recycling of the membrane required for epithelial cell formation in early Drosophila embryogenesis. We further investigate the functions of each of the domains of CenB1A in plasma membrane remodeling. We generated GFP-tagged constructs of the full-length and domain-deleted constructs of CenB1A. The localization and effects of these proteins on plasma membrane remodeling were observed in Drosophila S2 R+ cells. The GFP-CenB1A localised to the cytoplasm as well as to F-actin protrusions and resulted in long F-actin labeled plasma membrane protrusions. We observed that all the domain deletion transfections resulted in shorter protrusions. Further, we aim to study the effects of overexpression of different CenB1A domain deletions in membrane remodeling during early Drosophila embryogenesis. We observed that the CenB1A protein localizes to the plasma membrane, the cytoplasm, and also associates with the centrosomes or the pericentriolar region. Overexpression of BAR-PH deletion, ArfGAP deletion, or Ankyrin repeats in the background of CenB1A mutant resulted in trafficking defects in the embryos. Moreover, we observed that BAR-PH is required for membrane localization of the protein, ArfGAP is required for pericentriolar localization of the protein, and the Ankyrin repeats play a role in cytoplasmic recruitment of the protein. We find that both ArfGAP and Ankyrin domains are required for the endosomal recycling function of CenB1A.