Rab11 polarization of theDrosophilaoocyte: a novel link between membrane trafficking, microtubule organization, andoskarmRNA localization and translation

Abstract

The Drosophila embryonic body plan is specified by asymmetries that arise in the oocyte during oogenesis. These asymmetries are apparent in the subcellular distribution of key mRNAs and proteins and in the organization of the microtubule cytoskeleton. We present evidence that the Drosophila oocyte also contains important asymmetries in its membrane trafficking pathways. Specifically, we show that α-adaptin and Rab11, which function critically in the endocytic pathways of all previously examined animal cells, are localized to neighboring compartments at the posterior pole of stage 8-10 oocytes. Rab11 and α-adaptin localization occurs in the absence of a polarized microtubule cytoskeleton, i.e. in grk null mutants, but is later reinforced and/or refined by Osk, the localization of which is microtubule dependent. Analyses of germline clones of a rab11 partial loss-of-function mutation reveal a requirement for Rab11 in endocytic recycling and in the organization of posterior membrane compartments. Such analyses also reveal a requirement for Rab11 in the organization of microtubule plus ends and osk mRNA localization and translation. We propose that microtubule plus ends and, possibly, translation factors for osk mRNA are anchored to posterior membrane compartments that are defined by Rab11-mediated trafficking and reinforced by Rab11-Osk interactions.

Opposing functions for retromer and Rab11 in extracellular vesicle traffic at presynaptic terminals

“…We then asked whether aberrant sorting of EV cargo through this Rab11-positive compartment in Vps35 mutants caused its accumulation, by testing if levels could be restored by rebalancing the opposing activities of Rab11 and Vps35 in Vps35 ; rab11 double mutants. rab11 null mutants are embryonic lethal ( Dollar et al, 2002 ), precluding clean epistasis experiments, so we tested how these mechanisms interact using hypomorphic mutants. Strikingly, reduction of rab11 function in the Vps35 mutant significantly rescued both pre- and postsynaptic Syt4 and Nrg levels ( Fig.…”

Shotgun Ecotoxicoproteomics ofDaphnia pulex: Biochemical Effects of the Anticancer Drug Tamoxifen

“…Table S4 in the Supporting Information). These proteins have many functions related to vesicle and membrane trafficking, and, in particular, have been shown to be involved, with another down-regulated protein of our data set (maternal protein exuperantia, E9HLH8), in oocyte polarization, an essential step in embryo development. − Two other proteins playing an important role in oocyte development, E9H8M2 and E9G6B6, homologues to Drosophila aubergine and baiser proteins, respectively, were also clearly decreased after tamoxifen treatment.…”

Germline protein, Cup, non-cell autonomously limits migratory cell fate in Drosophila oogenesis

“…Endocytosis is a multistep process where the internalized cargo moves to early endosomes, where the cargo is either recycled back to the plasma membrane or directed to late endosome enroute to degradation(Bonifacino and Rojas 2006; Futter et al 1996; MacDonald, Savage, and Zech 2020; Ullrich et al 1996). Rab5 GTPase plays a crucial role in biogenesis of endosome and aids in the maturation of early endosomes to late endosomes (Bucci et al 1992) while Rab11 GTPase facilitates the recycling of the cargo from the early endosomes to the plasma membrane(Dollar et al 2002; Pasqualato et al 2004). The cargo that is marked for degradation moves from the late endosome to lysosome with the help of the activity of Rab7GTPase (Guerra and Bucci 2016).…”