TY - JOUR
T1 - Enhancement of β-catenin activity by BIG1 plus BIG2 via Arf activation and cAMP signals
AU - Li, Chun Chun
AU - Le, Kang
AU - Kato, Jiro
AU - Moss, Joel
AU - Vaughan, Martha
N1 - Funding Information:
This work was supported by NIH Grant R01DK074738, Broad Foundation Grant IBD-0328, and National Multiple Sclerosis Society Grant PP1779 (to K.S.K.), by the Texas AandM Clinical Science and Translational Research Institute, Texas AandM Genomics Grant Program, and the Center for Translational Environmental and Health Research (K.S.K.). S.Y. is the recipient of a fellowship from the Sumitomo Life Welfare and Culture Foundation. Blood Institute (NHLBI)] for their much appreciated assistance with confocal microscopy and Dr. Michael A. Frohman for expert advice on PLD inhibitors. This work was supported by the Intramural Research Program, NIH, NHLBI, and in part by the Taiwan Ministry of Science and Technology (Grants MOST 103-2320-B- 006-039-MY3 and MOST 104-2320-B-006-032-MY3) (to C.-C.L.).
PY - 2016/5/24
Y1 - 2016/5/24
N2 - Multifunctional β-catenin, with critical roles in both cell-cell adhesion and Wnt-signaling pathways, was among HeLa cell proteins coimmunoprecipitated by antibodies against brefeldin A-inhibited guanine nucleotide-exchange factors 1 and 2 (BIG1 or BIG2) that activate ADP-ribosylation factors (Arfs) by accelerating the replacement of bound GDP with GTP. BIG proteins also contain A-kinase anchoring protein (AKAP) sequences that can act as scaffolds for multimolecular assemblies that facilitate and limit cAMP signaling temporally and spatially. Direct interaction of BIG1 N-terminal sequence with β-catenin was confirmed using yeast two-hybrid assays and in vitro synthesized proteins. Depletion of BIG1 and/or BIG2 or overexpression of guanine nucleotide-exchange factor inactive mutant, but not wild-type, proteins interfered with β-catenin trafficking, leading to accumulation at perinuclear Golgi structures. Both phospholipase D activity and vesicular trafficking were required for effects of BIG1 and BIG2 on β-catenin activation. Levels of PKAphosphorylated β-catenin S675 and β-catenin association with PKA, BIG1, and BIG2 were also diminished after BIG1/BIG2 depletion. Inferring a requirement for BIG1 and/or BIG2 AKAP sequence in PKA modification of β-catenin and its effect on transcription activation, we confirmed dependence of S675 phosphorylation and transcription coactivator function on BIG2 AKAP-C sequence.
AB - Multifunctional β-catenin, with critical roles in both cell-cell adhesion and Wnt-signaling pathways, was among HeLa cell proteins coimmunoprecipitated by antibodies against brefeldin A-inhibited guanine nucleotide-exchange factors 1 and 2 (BIG1 or BIG2) that activate ADP-ribosylation factors (Arfs) by accelerating the replacement of bound GDP with GTP. BIG proteins also contain A-kinase anchoring protein (AKAP) sequences that can act as scaffolds for multimolecular assemblies that facilitate and limit cAMP signaling temporally and spatially. Direct interaction of BIG1 N-terminal sequence with β-catenin was confirmed using yeast two-hybrid assays and in vitro synthesized proteins. Depletion of BIG1 and/or BIG2 or overexpression of guanine nucleotide-exchange factor inactive mutant, but not wild-type, proteins interfered with β-catenin trafficking, leading to accumulation at perinuclear Golgi structures. Both phospholipase D activity and vesicular trafficking were required for effects of BIG1 and BIG2 on β-catenin activation. Levels of PKAphosphorylated β-catenin S675 and β-catenin association with PKA, BIG1, and BIG2 were also diminished after BIG1/BIG2 depletion. Inferring a requirement for BIG1 and/or BIG2 AKAP sequence in PKA modification of β-catenin and its effect on transcription activation, we confirmed dependence of S675 phosphorylation and transcription coactivator function on BIG2 AKAP-C sequence.
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U2 - 10.1073/pnas.1601918113
DO - 10.1073/pnas.1601918113
M3 - Article
C2 - 27162341
AN - SCOPUS:84969856756
SN - 0027-8424
VL - 113
SP - 5946
EP - 5951
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 21
ER -