scholarly journals Arf3 Is Activated Uniquely at the trans-Golgi Network by Brefeldin A-inhibited Guanine Nucleotide Exchange Factors

2010 ◽  
Vol 21 (11) ◽  
pp. 1836-1849 ◽  
Author(s):  
Florin Manolea ◽  
Justin Chun ◽  
David W. Chen ◽  
Ian Clarke ◽  
Nathan Summerfeldt ◽  
...  
Keyword(s):  
Guanine Nucleotide Exchange Factors ◽  
Temperature Sensitive ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Membrane Composition ◽  
Trans Golgi Network ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factors ◽  
Golgi Membranes ◽  
Golgi Network

It is widely assumed that class I and II Arfs function interchangeably throughout the Golgi complex. However, we report here that in vivo, Arf3 displays several unexpected properties. Unlike other Golgi-localized Arfs, Arf3 associates selectively with membranes of the trans-Golgi network (TGN) in a manner that is both temperature-sensitive and uniquely dependent on guanine nucleotide exchange factors of the BIGs family. For example, BIGs knockdown redistributed Arf3 but not Arf1 from Golgi membranes. Furthermore, shifting temperature to 20°C, a temperature known to block cargo in the TGN, selectively redistributed Arf3 from Golgi membranes. Arf3 redistribution occurred slowly, suggesting it resulted from a change in membrane composition. Arf3 knockdown and overexpression experiments suggest that redistribution is not responsible for the 20°C block. To investigate in more detail the mechanism for Arf3 recruitment and temperature-dependent release, we characterized several mutant forms of Arf3. This analysis demonstrated that those properties are readily separated and depend on pairs of residues present at opposite ends of the protein. Furthermore, phylogenetic analysis established that all four critical residues were absolutely conserved and unique to Arf3. These results suggest that Arf3 plays a unique function at the TGN that likely involves recruitment by a specific receptor.

scholarly journals Characterization of RIN3 as a Guanine Nucleotide Exchange Factor for the Rab5 Subfamily GTPase Rab31

2011 ◽  
Vol 286 (27) ◽  
pp. 24364-24373 ◽  
Author(s):  
Hiroaki Kajiho ◽  
Kyoko Sakurai ◽  
Tomohiro Minoda ◽  
Manabu Yoshikawa ◽  
Satoshi Nakagawa ◽  
...  
Keyword(s):  
Guanine Nucleotide Exchange Factors ◽  
Endocytic Pathway ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Trans Golgi Network ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factors ◽  
Early Endosomes ◽  
Vacuolar Protein ◽  
Golgi Network

The small GTPase Rab5, which cycles between GDP-bound inactive and GTP-bound active forms, plays essential roles in membrane budding and trafficking in the early endocytic pathway. Rab5 is activated by various vacuolar protein sorting 9 (VPS9) domain-containing guanine nucleotide exchange factors. Rab21, Rab22, and Rab31 (members of the Rab5 subfamily) are also involved in the trafficking of early endosomes. Mechanisms controlling the activation Rab5 subfamily members remain unclear. RIN (Ras and Rab interactor) represents a family of multifunctional proteins that have a VPS9 domain in addition to Src homology 2 (SH2) and Ras association domains. We investigated whether RIN family members act as guanine nucleotide exchange factors (GEFs) for the Rab5 subfamily on biochemical and cell morphological levels. RIN3 stimulated the formation of GTP-bound Rab31 in cell-free and in cell GEF activity assays. RIN3 also formed enlarged vesicles and tubular structures, where it colocalized with Rab31 in HeLa cells. In contrast, RIN3 did not exhibit any apparent effects on Rab21. We also found that serine to alanine substitutions in the sequences between SH2 and RIN family homology domain of RIN3 specifically abolished its GEF action on Rab31 but not Rab5. We examined whether RIN3 affects localization of the cation-dependent mannose 6-phosphate receptor (CD-MPR), which is transported between trans-Golgi network and endocytic compartments. We found that RIN3 partially translocates CD-MPR from the trans-Golgi network to peripheral vesicles and that this is dependent on its Rab31-GEF activity. These results indicate that RIN3 specifically acts as a GEF for Rab31.

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

2008 ◽  
Vol 19 (6) ◽  
pp. 2650-2660 ◽  
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.

scholarly journals The ADP Ribosylation Factor-Nucleotide Exchange Factors Gea1p and Gea2p Have Overlapping, but Not Redundant Functions in Retrograde Transport from the Golgi to the Endoplasmic Reticulum

2001 ◽  
Vol 12 (4) ◽  
pp. 1035-1045 ◽  
Author(s):  
Anne Spang ◽  
Johannes M. Herrmann ◽  
Susan Hamamoto ◽  
Randy Schekman
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Transport ◽  
Retrograde Transport ◽  
Guanine Nucleotide Exchange Factors ◽  
Temperature Sensitive ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factors ◽  
Membrane Bound

The activation of the small ras-like GTPase Arf1p requires the action of guanine nucleotide exchange factors. Four Arf1p guanine nucleotide exchange factors have been identified in yeast: Sec7p, Syt1p, Gea1p, and its homologue Gea2p. We identifiedGEA2 as a multicopy suppressor of asec21-3 temperature-sensitive mutant.SEC21 encodes the γ-subunit of coatomer, a heptameric protein complex that together with Arf1p forms the COPI coat.GEA1 and GEA2 have at least partially overlapping functions, because deletion of either gene results in no obvious phenotype, whereas the double null mutant is inviable. Conditional mutants defective in both GEA1 andGEA2 accumulate endoplasmic reticulum and Golgi membranes under restrictive conditions. The two genes do not serve completely overlapping functions because a Δgea1Δarf1 mutant is not more sickly than a Δarf1 strain, whereas Δgea2Δarf1 is inviable. Biochemical experiments revealed similar distributions and activities for the two proteins. Gea1p and Gea2p exist both in membrane-bound and in soluble forms. The membrane-bound forms, at least one of which, Gea2p, can be visualized on Golgi structures, are both required for vesicle budding and protein transport from the Golgi to the endoplasmic reticulum. In contrast, Sec7p, which is required for protein transport within the Golgi, is not required for retrograde protein trafficking.

scholarly journals Involvement of the Switch 2 Domain of Ras in Its Interaction with Guanine Nucleotide Exchange Factors

1996 ◽  
Vol 271 (19) ◽  
pp. 11076-11082 ◽  
Author(s):  
Lawrence A. Quilliam ◽  
Mark M. Hisaka ◽  
Sheng Zhong ◽  
Amy Lowry ◽  
Raymond D. Mosteller ◽  
...  
Keyword(s):  
Guanine Nucleotide Exchange Factors ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factors

scholarly journals Essential Role of Vav Family Guanine Nucleotide Exchange Factors in EphA Receptor-Mediated Angiogenesis

2006 ◽  
Vol 26 (13) ◽  
pp. 4830-4842 ◽  
Author(s):  
Sonja G. Hunter ◽  
Guanglei Zhuang ◽  
Dana Brantley-Sieders ◽  
Wojciech Swat ◽  
Christopher W. Cowan ◽  
...  
Keyword(s):  
Guanine Nucleotide Exchange Factors ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factors ◽  
Rac1 Gtpase ◽  
Rho Family ◽  
Epha Receptor

ABSTRACT Angiogenesis, the process by which new blood vessels are formed from preexisting vasculature, is critical for vascular remodeling during development and contributes to the pathogenesis of diseases such as cancer. Prior studies from our laboratory demonstrate that the EphA2 receptor tyrosine kinase is a key regulator of angiogenesis in vivo. The EphA receptor-mediated angiogenic response is dependent on activation of Rho family GTPase Rac1 and is regulated by phosphatidylinositol 3-kinase. Here we report the identification of Vav2 and Vav3 as guanine nucleotide exchange factors (GEFs) that link the EphA2 receptor to Rho family GTPase activation and angiogenesis. Ephrin-A1 stimulation recruits the binding of Vav proteins to the activated EphA2 receptor. The induced association of EphA receptor and Vav proteins modulates the activity of Vav GEFs, leading to activation of Rac1 GTPase. Overexpression of either Vav2 or Vav3 in primary microvascular endothelial cells promotes Rac1 activation, cell migration, and assembly in response to ephrin-A1 stimulation. Conversely, loss of Vav2 and Vav3 GEFs inhibits Rac1 activation and ephrin-A1-induced angiogenic responses both in vitro and in vivo. In addition, embryonic fibroblasts derived from Vav2−/− Vav3−/− mice fail to spread on an ephrin-A1-coated surface and exhibit a significant decrease in the formation of ephrin-A1-induced lamellipodia and filopodia. These findings suggest that Vav GEFs serve as a molecular link between EphA2 receptors and the actin cytoskeleton and provide an important mechanism for EphA2-mediated angiogenesis.

Family-wide Analysis of the Inhibition of Arf Guanine Nucleotide Exchange Factors with Small Molecules: Evidence of Unique Inhibitory Profiles

Biochemistry ◽  
2017 ◽  
Vol 56 (38) ◽  
pp. 5125-5133 ◽  
Author(s):  
Sarah Benabdi ◽  
François Peurois ◽  
Agata Nawrotek ◽  
Jahnavi Chikireddy ◽  
Tatiana Cañeque ◽  
...  
Keyword(s):  
Small Molecules ◽  
Guanine Nucleotide Exchange Factors ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factors

scholarly journals Activation of G proteins by guanine nucleotide exchange factors relies on GTPase activity

2015 ◽  
Author(s):  
Rob J Stanley ◽  
Geraint MH Thomas
Keyword(s):  
G Protein ◽  
G Proteins ◽  
Guanine Nucleotide Exchange Factors ◽  
Guanine Nucleotide ◽  
Gtpase Activity ◽  
Nucleotide Exchange ◽  
Signalling Molecules ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factors ◽  
Experimental Strategies

G proteins are an important family of signalling molecules controlled by guanine nucleotide exchange and GTPase activity in what is commonly called an 'activation/inactivation cycle'. The molecular mechanism by which guanine nucleotide exchange factors (GEFs) catalyse the activation of monomeric G proteins is well-established, however the complete reversibility of this mechanism is often overlooked. Here, we use a theoretical approach to prove that GEFs are unable to positively control G protein systems at steady-state in the absence of GTPase activity. Instead, positive regulation of G proteins must be seen as a product of the competition between guanine nucleotide exchange and GTPase activity -- emphasising a central role for GTPase activity beyond merely signal termination. We conclude that a more accurate description of the regulation of G proteins via these processes is as a 'balance/imbalance' mechanism. This result has implications for the understanding of many intracellular signalling processes, and for experimental strategies that rely on modulating G protein systems.

scholarly journals Tankyrase regulates epithelial lumen formation via suppression of Rab11 GEFs

2021 ◽  
Vol 220 (7) ◽  
Author(s):  
Arun A. Chandrakumar ◽  
Étienne Coyaud ◽  
Christopher B. Marshall ◽  
Mitsuhiko Ikura ◽  
Brian Raught ◽  
...  
Keyword(s):  
Guanine Nucleotide Exchange Factors ◽  
Protein Abundance ◽  
Epithelial Polarity ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Lumen Formation ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factors ◽  
Interaction Proteomics ◽  
Sequential Inhibition

Rab11 GTPase proteins are required for cytokinesis, ciliogenesis, and lumenogenesis. Rab11a is critical for apical delivery of podocalyxin (PODXL) during lumen formation in epithelial cells. SH3BP5 and SH3BP5L are guanine nucleotide exchange factors (GEFs) for Rab11. We show that SH3BP5 and SH3BP5L are required for activation of Rab11a and cyst lumen formation. Using proximity-dependent biotin identification (BioID) interaction proteomics, we have identified SH3BP5 and its paralogue SH3BP5L as new substrates of the poly-ADP-ribose polymerase Tankyrase and the E3 ligase RNF146. We provide data demonstrating that epithelial polarity via cyst lumen formation is governed by Tankyrase, which inhibits Rab11a activation through the suppression of SH3BP5 and SH3BP5L. RNF146 reduces Tankyrase protein abundance and restores Rab11a activation and lumen formation. Thus, Rab11a activation is controlled by a signaling pathway composed of the sequential inhibition of SH3BP5 paralogues by Tankyrase, which is itself suppressed by RNF146.

Sign in / Sign up

Export Citation Format

Share Document