Role ofBicDRin bristle shaft construction, tracheal development, and support ofBicDfunctions

Abstract

AbstractCell polarization requires asymmetric localization of numerous mRNAs, proteins, and organelles. The movement of cargo towards the minus end of microtubules mostly depends on cytoplasmic dynein motors, which function as multiprotein complexes. In the dynein/dynactin/Bicaudal-D (DDB) transport machinery, Bicaudal-D (BicD) links the cargo to the motor. Here we focus on the role ofBicD-related(BicDR) and its contribution to microtubule-dependent transport processes.Drosophila BicDRis required for the normal development of bristles and dorsal trunk tracheae. Together withBicD,it contributes to the organization and stability of the actin cytoskeleton in the not-yet-chitinized bristle shaft and the localization of Spn-F and Rab6 at the distal tip. We show thatBicDRsupports the function ofBicDin bristle development and our results suggest that BicDR transports cargo more locally whereas BicD is more responsible for delivering functional cargo over the long distance to the distal tip. We identified the proteins that interact with BicDR and appear to be BicDR cargo in embryonic tissues. For one of them, EF1γ, we showed thatEF1γgenetically interacts with BicD andBicDRin the construction of the bristles.