A Rab11-GEF Parcas recruits Rab11 onto recycling endosomes for rhodopsin transport in Drosophila photoreceptors

Rab11 and its effectors dRip11 and MyoV are essential for polarized post-Golgi vesicle trafficking to photosensitive membrane rhabdomeres in Drosophila photoreceptors. Here, we found that Parcas (Pcs), recently shown to have guanine-nucleotide-exchange (GEF) activity toward Rab11, co-localizes with Rab11 on the trans-side of Golgi units and post-Golgi vesicles at the base of the rhabdomeres in pupal photoreceptors. Pcs fused with the EM-tag APEX2 localizes on 150-300 nm vesicles at the trans-side of Golgi units, which are presumably fly recycling endosomes (RE). Loss of Pcs impairs Rab11 localization on the trans-side of Golgi units and induces the cytoplasmic accumulation of post-Golgi vesicles bearing rhabdomere proteins, as observed in Rab11-deficiency. In contrast, loss of the specific subunits of TRAPPII, another known Rab11-GEF, does not cause any defects on the eye development nor the transport of rhabdomere proteins, however, simultaneous loss of TRAPPII and Pcs shows severe defects on eye development. These results indicated that in pupal photoreceptors, Pcs is the predominant Rab11-GEF, and TRAPPII performs a function that is redundant but subsidiary to that of Pcs.

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ARF-GEF cytohesin-2/ARNO regulates R-Ras and α5-integrin recycling through an EHD1-positive compartment

Molecular Biology of the Cell ◽

10.1091/mbc.e15-05-0278 ◽

2015 ◽

Vol 26 (23) ◽

pp. 4265-4279 ◽

Cited By ~ 5

Author(s):

Joseph C. Salem ◽

Marta M. Reviriego-Mendoza ◽

Lorraine C. Santy

Keyword(s):

Adhesion Formation ◽

Small Gtpases ◽

Guanine Nucleotide ◽

Nucleotide Exchange ◽

Recycling Endosomes ◽

Guanine Nucleotide Exchange ◽

Nucleotide Exchange Factor ◽

And Migration ◽

Regulated Trafficking ◽

Migration Response

When expressed in epithelial cells, cytohesin-2/ARNO, a guanine nucleotide exchange factor (GEF) for ARF small GTPases, causes a robust migration response. Recent evidence suggests that cytohesin-2/ARNO acts downstream of small the GTPase R-Ras to promote spreading and migration. We hypothesized that cytohesin-2/ARNO could transmit R-Ras signals by regulating the recycling of R-Ras through ARF activation. We found that Eps15-homology domain 1 (EHD1), a protein that associates with the endocytic recycling compartment (ERC), colocalizes with active R-Ras in transiently expressed HeLa cells. In addition, we show that EHD1-positive recycling endosomes are a novel compartment for cytohesin-2/ARNO. Knockdown or expression of GEF-inactive (E156K) cytohesin-2/ARNO causes R-Ras to accumulate on recycling endosomes containing EHD1 and inhibits cell spreading. E156K-ARNO also causes a reduction in focal adhesion size and number. Finally, we demonstrate that R-Ras/ARNO signaling is required for recycling of α5-integrin and R-Ras to the plasma membrane. These data establish a role for cytohesin-2/ARNO as a regulator of R-Ras and integrin recycling and suggest that ARF-regulated trafficking of R-Ras is required for R-Ras–dependent effects on spreading and adhesion formation.

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Redundant Roles of BIG2 and BIG1, Guanine-Nucleotide Exchange Factors for ADP-Ribosylation Factors in Membrane Traffic between the trans-Golgi Network and Endosomes

Molecular Biology of the Cell ◽

10.1091/mbc.e07-10-1067 ◽

2008 ◽

Vol 19 (6) ◽

pp. 2650-2660 ◽

Cited By ~ 62

Author(s):

Ray Ishizaki ◽

Hye-Won Shin ◽

Hiroko Mitsuhashi ◽

Kazuhisa Nakayama

Keyword(s):

Membrane Traffic ◽

Guanine Nucleotide Exchange Factors ◽

Guanine Nucleotide ◽

Nucleotide Exchange ◽

Recycling Endosomes ◽

Adp Ribosylation ◽

Trans Golgi Network ◽

Guanine Nucleotide Exchange ◽

Nucleotide Exchange Factors ◽

Golgi Network

BIG2 and BIG1 are closely related guanine-nucleotide exchange factors (GEFs) for ADP-ribosylation factors (ARFs) and are involved in the regulation of membrane traffic through activating ARFs and recruiting coat protein complexes, such as the COPI complex and the AP-1 clathrin adaptor complex. Although both ARF-GEFs are associated mainly with the trans-Golgi network (TGN) and BIG2 is also associated with recycling endosomes, it is unclear whether BIG2 and BIG1 share some roles in membrane traffic. We here show that knockdown of both BIG2 and BIG1 by RNAi causes mislocalization of a subset of proteins associated with the TGN and recycling endosomes and blocks retrograde transport of furin from late endosomes to the TGN. Similar mislocalization and protein transport block, including furin, were observed in cells depleted of AP-1. Taken together with previous reports, these observations indicate that BIG2 and BIG1 play redundant roles in trafficking between the TGN and endosomes that involves the AP-1 complex.

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Structural basis of guanine nucleotide exchange for Rab11 by SH3BP5

Life Science Alliance ◽

10.26508/lsa.201900297 ◽

2019 ◽

Vol 2 (2) ◽

pp. e201900297 ◽

Cited By ~ 1

Author(s):

Sakurako Goto-Ito ◽

Nobukatsu Morooka ◽

Atsushi Yamagata ◽

Yusuke Sato ◽

Ken Sato ◽

...

Keyword(s):

Coiled Coil ◽

Site Directed Mutagenesis ◽

Structural Basis ◽

Rab Gtpase ◽

Guanine Nucleotide ◽

Nucleotide Exchange ◽

Recycling Endosomes ◽

Guanine Nucleotide Exchange ◽

Nucleotide Exchange Factors ◽

Endosomal Recycling

The Rab GTPase family is a major regulator of membrane traffic in eukaryotic cells. The Rab11 subfamily plays important roles in specific trafficking events such as exocytosis, endosomal recycling, and cytokinesis. SH3BP5 and SH3BP5-like (SH3BP5L) proteins have recently been found to serve as guanine nucleotide exchange factors (GEF) for Rab11. Here, we report the crystal structures of the SH3BP5 GEF domain alone and its complex with Rab11a. SH3BP5 exhibits a V-shaped structure comprising two coiled coils. The coiled coil composed of α1, and α4 is solely responsible for the Rab11a binding and GEF activity. SH3BP5 pulls out and deforms switch I of Rab11a so as to facilitate the GDP release from Rab11a. SH3BP5 interacts with the N-terminal region, switch I, interswitch, and switch II of Rab11a. SH3BP5 and SH3BP5L localize to Rab11-positive recycling endosomes and show GEF activity for all of the Rab11 family but not for Rab14. Fluorescence-based GEF assays combined with site-directed mutagenesis reveal the essential interactions between SH3BP5 and Rab11 family proteins for the GEF reaction on recycling endosomes.

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