| 2003 |
ARFGEF2/BIG2 is required for vesicle and membrane trafficking from the trans-Golgi network (TGN); inhibition by brefeldin A or dominant-negative ARFGEF2 cDNA decreases neural progenitor cell proliferation in vitro and disrupts intracellular localization of E-cadherin and beta-catenin by preventing their transport from the Golgi apparatus to the cell surface. |
Dominant-negative cDNA expression, brefeldin A inhibition, cell proliferation assays, immunofluorescence localization of E-cadherin and beta-catenin in cultured cells |
Nature genetics |
High |
14647276
|
| 2002 |
BIG2 overexpression blocks BFA-induced redistribution of ARF1 and the AP-1 complex from TGN membranes but not the COPI complex, indicating BIG2 specifically regulates membrane association of AP-1 (but not COPI) through ARF activation at the TGN. |
Overexpression of BIG2 in cells, BFA treatment, immunofluorescence redistribution assays for ARF1, AP-1, and COPI coat proteins |
The Journal of biological chemistry |
Medium |
11777925
|
| 2002 |
A dominant-negative BIG2 mutant induces redistribution of AP-1 and GGA1 coat proteins and membrane tubulation of the TGN, but does not affect COPI redistribution or Golgi tubulation, placing BIG2 specifically in the TGN-to-endosome trafficking pathway via AP-1 and GGA regulation. |
Dominant-negative BIG2 mutant expression, immunofluorescence for AP-1, GGA1, COPI, organelle markers |
Biochemical and biophysical research communications |
Medium |
12051703
|
| 2004 |
BIG2 localizes to both the TGN and recycling endosomes; expression of a catalytically inactive BIG2 mutant (E738K) selectively induces membrane tubules from the recycling endosome compartment. BIG2 has exchange activity toward class I ARFs (ARF1 and ARF3) in vivo, and inactivation of either ARF exaggerates tubulation induced by BIG2(E738K), indicating BIG2 maintains recycling endosome integrity via class I ARF activation. |
Catalytically inactive mutant (E738K) expression, immunofluorescence, ARF1/ARF3 inactivation epistasis, subcellular fractionation/localization |
Molecular biology of the cell |
High |
15385626
|
| 2003 |
BIG2 contains three A kinase-anchoring protein (AKAP) domains in its N-terminal region: domain A (residues 27–48) interacts with RI-alpha and RI-beta; domain B (284–301) interacts with RII-alpha and RII-beta; domain C (517–538) interacts with RI-alpha, RII-alpha, and RII-beta. BIG2 physically interacts with the PKA regulatory subunit RI-alpha, confirmed by coimmunoprecipitation of in vitro translated proteins and endogenous proteins. Elevation of cAMP (8-Br-cAMP or forskolin) induces translocation of BIG2 from cytosol to Golgi and other membranes. |
Yeast two-hybrid screen, coimmunoprecipitation of in vitro translated and endogenous proteins, 28 deletion mutants, Western blot subcellular fractionation |
Proceedings of the National Academy of Sciences of the United States of America |
High |
12571360
|
| 2005 |
BIG2 physically interacts with exocyst protein Exo70 via its N-terminal region (amino acids 1–643); both BIG2 and Exo70 co-localize at trans-Golgi network membranes and at the microtubule-organizing center (MTOC)/centrosomes in HepG2 cells, suggesting functional association in vesicular trafficking from TGN to plasma membrane. |
Yeast two-hybrid screen, coimmunoprecipitation of in vitro translated proteins, immunofluorescence confocal microscopy, centrosome purification |
Proceedings of the National Academy of Sciences of the United States of America |
Medium |
15705715
|
| 2006 |
BIG2 localizes specifically (not BIG1) to recycling endosome structures during transferrin uptake and transferrin receptor (TfnR) recycling in COS7 cells. BIG2 siRNA knockdown causes perinuclear accumulation of TfnR and significantly slows transferrin release, demonstrating a functional role for BIG2 in TfnR recycling. BIG2 interacts with Exo70 in recycling endosome fractions. |
Immunofluorescence microscopy, density-gradient fractionation, siRNA knockdown, transferrin recycling assay |
Proceedings of the National Academy of Sciences of the United States of America |
High |
16477018
|
| 2006 |
BIG2 (but not BIG1) is required for trafficking of Filamin A (FLNA) from the Golgi apparatus to the cell membrane in neuroblastoma cells; transfection of dominant-negative ARFGEF2 partially blocks FLNA transport. BIG2 and FLNA are co-expressed in neural progenitors along the neuroependyma. |
Dominant-negative ARFGEF2 transfection, immunofluorescence for FLNA localization, Western blot co-expression |
The Journal of comparative neurology |
Medium |
16320251
|
| 2007 |
BIG2 (not BIG1) regulates constitutive release of TNFR1 exosome-like vesicles from human vascular endothelial cells via an ARF1- and ARF3-dependent mechanism. BIG2 co-localizes with TNFR1 in cytoplasmic vesicles, and this association is disrupted by BFA. ARF1 and ARF3 act nonredundantly and additively in TNFR1 exosome-like vesicle release. |
RNA interference (specific siRNA for BIG1, BIG2, ARF1, ARF3), TNFR1 release assay, immunofluorescence co-localization, BFA disruption |
The Journal of biological chemistry |
High |
17276987
|
| 2007 |
PKA phosphorylates BIG2 in vitro, decreasing its GEP activity; this phosphorylation is reversed by protein phosphatase 1gamma (PP1gamma) but not PP1alpha or PP1beta. Endogenous PP1gamma (not PP1alpha or PP1beta) co-immunoprecipitates with BIG2 from microsomal fractions, establishing PP1gamma as a regulator of BIG2 activity. |
In vitro PKA phosphorylation assay, siRNA depletion of BIG2, immunoprecipitation GEP activity assay, recombinant phosphatase treatment, Co-IP of PP1 isoforms |
Proceedings of the National Academy of Sciences of the United States of America |
High |
17360629
|
| 2006 |
AMY-1 (associate of Myc-1) co-immunoprecipitates with both BIG2 and BIG1 in vitro, but localizes to the TGN specifically through interaction with BIG2 (not BIG1) as demonstrated by RNAi: depletion of BIG2 (not BIG1) disperses AMY-1 from the TGN. |
Co-immunoprecipitation using FLAG-tagged AMY-1, siRNA knockdown of BIG1 or BIG2, immunofluorescence localization of AMY-1 |
Genes to cells : devoted to molecular & cellular mechanisms |
Medium |
16866877
|
| 2007 |
BIG2 (and BIG1) form homodimers through interactions between their conserved DCB domains; within each homodimer, the DCB domain also interacts with the HUS domain. The HUS box is the most conserved motif in large ArfGEFs after the Sec7 domain and mediates the DCB/HUS interaction. |
Yeast two-hybrid assays, biochemical interaction assays, deletion mutant analysis, cellular dimerization assays in mammalian cells |
The Journal of biological chemistry |
Medium |
17640864
|
| 2008 |
Simultaneous knockdown of both BIG2 and BIG1 causes mislocalization of TGN/recycling endosome-associated proteins and blocks retrograde transport of furin from late endosomes to the TGN, a phenotype similar to depletion of AP-1, establishing BIG2 and BIG1 as redundant regulators of AP-1-dependent trafficking between TGN and endosomes. |
RNAi double knockdown, immunofluorescence localization of furin and TGN markers, comparison to AP-1 depletion |
Molecular biology of the cell |
Medium |
18417613
|
| 2008 |
cAMP-induced release of TNFR1 exosome-like vesicles requires PKA activity and is mediated through BIG2's AKAP function: PKA regulatory subunit RIIbeta binds specifically to BIG2 AKAP domains B and C, and this interaction is required for both constitutive and cAMP-induced TNFR1 exosome-like vesicle release. |
siRNA knockdown of PKA regulatory subunits (RIIbeta), TNFR1 release assay, domain mapping of BIG2 AKAP sequences, 8-bromo-cAMP stimulation |
The Journal of biological chemistry |
Medium |
18625701
|
| 2009 |
Phosphodiesterase 3A (PDE3A) physically associates with BIG2 (and BIG1) complexes; specific depletion of PDE3A by siRNA or its inhibition by cilostamide significantly decreases membrane-associated BIG2 and BIG1 and reduces activated ARF1-GTP, linking PDE3A-dependent cAMP regulation within BIG2 AKAP complexes to ARF1 activation. |
siRNA depletion of PDE3A, PDE3A-specific inhibitor cilostamide, confocal immunofluorescence, ARF1-GTP measurement |
Proceedings of the National Academy of Sciences of the United States of America |
Medium |
19332778
|
| 2010 |
Depletion of BIG2 (but not BIG1) by siRNA induces tubulation of the recycling endosomal compartment, while BIG1 depletion causes Golgi fragmentation into mini-stacks; this demonstrates non-redundant and distinct functions for BIG2 (recycling endosome integrity) vs. BIG1 (Golgi morphology). |
siRNA knockdown, fixed and live-cell fluorescence imaging of Golgi and endosomal markers |
PloS one |
Medium |
20360857
|
| 2012 |
The small G protein Arl1 is necessary and sufficient for Golgi recruitment of BIG2 (and BIG1) but not GBF1. Arl1 binds directly to the N-terminal region of Sec71 (the Drosophila ortholog of BIG1/BIG2), establishing Arl1 as the upstream recruiter that directs BIG2 specifically to the trans-Golgi. |
Liposome-based affinity purification to identify Arl1 effectors, Arl1 knockdown in mammalian cells, immunofluorescence of BIG1/BIG2/GBF1 Golgi localization |
The Journal of cell biology |
High |
22291037
|
| 2012 |
BIG2 siRNA depletion causes perinuclear accumulation of integrin beta1 and delayed return to the cell surface, decreased cell motility, and reduced actin-based membrane protrusions; cytosolic levels of Arp2, Arp3, cofilin-1, phosphocofilin, vinculin, and Grb2 are increased, establishing BIG2 as a regulator of integrin beta1 recycling and actin dynamics in cell migration. |
siRNA knockdown, difference gel electrophoresis (DIGE) proteomics, immunofluorescence, wound-healing migration assay, integrin beta1 trafficking assay |
Proceedings of the National Academy of Sciences of the United States of America |
Medium |
22908276
|
| 2013 |
GBF1-activated ARFs (ARF4 and ARF5, but not ARF3) facilitate BIG2 and BIG1 recruitment to the TGN, establishing a functional GEF cascade: GBF1 (pre-Golgi/Golgi/TGN) → ARF4/ARF5 activation → BIG1/BIG2 TGN recruitment → ARF activation for AP-1/GGA clathrin adaptor recruitment. |
GBF1 dominant-negative expression, ARF isoform-specific depletion, immunofluorescence of BIG1/BIG2 TGN localization, ultrastructural localization by immuno-EM |
The Journal of biological chemistry |
Medium |
23386609
|
| 2013 |
BIG2 physically associates (reciprocal Co-IP) with nonmuscle myosin IIA in HeLa cells independently of its ARF-GEF activity; depletion of BIG2 (or BIG1) enhances phosphorylation of myosin regulatory light chain (T18/S19) and increases F-actin content, impairing cell migration. BIG2 anchors a myosin phosphatase complex containing myosin IIA, protein phosphatase 1delta, and myosin phosphatase-targeting subunit 1 (MYPT1). |
Reciprocal Co-IP of endogenous proteins, siRNA depletion, phospho-myosin light chain measurement, F-actin quantification, Transwell cell migration assay, rescue by BIG2 C-terminal overexpression |
Proceedings of the National Academy of Sciences of the United States of America |
High |
23918382
|
| 2016 |
BIG2 (and BIG1) physically interact with beta-catenin; depletion of BIG1/BIG2 or expression of GEF-inactive mutants causes perinuclear Golgi accumulation of beta-catenin and reduces PKA-phosphorylated beta-catenin (S675). BIG2 AKAP-C sequence is required for PKA-dependent S675 phosphorylation and beta-catenin transcription coactivator function, requiring both ARF-GEF activity and phospholipase D-dependent vesicular trafficking. |
Co-IP (BIG1/BIG2 antibodies), yeast two-hybrid, in vitro protein synthesis, siRNA depletion, GEF-inactive mutant expression, phospho-beta-catenin Western blot, transcription reporter assay |
Proceedings of the National Academy of Sciences of the United States of America |
Medium |
27162341
|
| 2018 |
BIG2 co-localizes with the Golgi apparatus in hippocampal neurons and is required for Golgi deployment into major dendrites. BIG2 acts through ARF1 to activate RhoA and its downstream effector mDia1, forming a BIG2-ARF1-RhoA-mDia1 signaling axis that regulates dendritic Golgi polarization and dendrite growth/maintenance. In vivo, ARFGEF2 shRNA delivered by in utero electroporation impairs Golgi deployment into the apical dendrite. |
shRNA knockdown, constitutively active ARF1 Q71L rescue, RhoA activation assay, LPA treatment rescue, immunofluorescence, in utero electroporation in mouse embryos |
Molecular neurobiology |
Medium |
29455446
|
| 2019 |
BIG2 (and BIG1) knockdown significantly decreases VEGF mRNA and protein levels in glioblastoma U251 cells and HUVECs, and inhibits HUVEC angiogenesis by diminishing cell migration. Knockdown of the BIG2 homolog arfgef2 in zebrafish impairs angioblast migration and intersegmental vessel sprouting, and CRISPR/Cas9 deletion of arfgef2 causes vascular development defects, establishing a role for BIG2 in VEGF expression and angiogenesis beyond vesicular trafficking. |
siRNA knockdown, VEGF mRNA/protein quantification, HUVEC migration and angiogenesis assays, zebrafish morpholino knockdown and CRISPR/Cas9 deletion with vascular GFP imaging |
FASEB journal |
Medium |
31199673
|
| 2025 |
In Drosophila neuroblasts, Arf1 and its GEF ARFGEF2/Sec71 control asymmetric division by facilitating cortical localization of nonmuscle myosin II regulatory light chain (Sqh). Arf1 physically associates with Sqh and with Vibrator (a type I PITP), and Arf1/Sec71 facilitate PI(4)P localization to the neuroblast cortex, linking PI(4)P production to myosin II cortical anchoring during asymmetric division. |
Genetic epistasis in Drosophila, Co-immunoprecipitation of Arf1 with Sqh and Vibrator, immunofluorescence of PI(4)P and myosin II cortical localization, loss-of-function neuroblast division assays |
Proceedings of the National Academy of Sciences of the United States of America |
Medium |
40208939
|