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Vuong TA, Lee SJ, Leem YE, Lee JR, Bae GU, Kang JS. SGTb regulates a surface localization of a guidance receptor BOC to promote neurite outgrowth. Cell Signal 2019; 55:100-108. [PMID: 30639199 DOI: 10.1016/j.cellsig.2019.01.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/02/2019] [Accepted: 01/05/2019] [Indexed: 01/07/2023]
Abstract
Neuritogenesis is a critical event for neuronal differentiation and neuronal circuitry formation during neuronal development and regeneration. Our previous study revealed a critical role of a guidance receptor BOC in a neuronal differentiation and neurite outgrowth. However, regulatory mechanisms for BOC signaling pathway remain largely unexplored. In the current study, we have identified Small glutamine-rich tetratricopeptide repeat (TPR)-containing b (SGTb) as a BOC interacting protein through yeast two-hybrid screening. Like BOC, SGTb is highly expressed in brain and P19 embryonal carcinoma (EC) cells differentiated into neuronal cells. BOC and SGTb proteins co-precipitate in mouse brain and differentiated P19 EC cells. Furthermore, BOC and SGTb co-localize in neurites and especially are concentrated at the tip of neurites in various neuronal cells. SGTb depletion attenuates neuronal differentiation of P19 cells through reduction of the surface level of BOC. Additionally, SGTb depletion causes BOC localization at neurite tip, coinciding with decreased p-JNK levels critical for actin cytoskeleton remodeling. The overexpression of SGTb or BOC restores JNK activation in BOC or SGTb-depleted cells, respectively. Finally, SGTb elevates the level of surface-resident BOC in BOC-depleted cells, restoring JNK activation. Taken together, our data suggest that SGTb interacts with BOC and regulates its surface level and consequent JNK activation, thereby promoting neuronal differentiation and neurite outgrowth.
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Affiliation(s)
- Tuan Anh Vuong
- Department of Molecular Cell Biology, Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea
| | - Sang-Jin Lee
- Research Institute of Pharmaceutical Science, College of Pharmacy, Sookmyung Women's University, Seoul 04310, Republic of Korea
| | - Young-Eun Leem
- Department of Molecular Cell Biology, Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea
| | - Jae-Rin Lee
- Department of Molecular Cell Biology, Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea
| | - Gyu-Un Bae
- Research Institute of Pharmaceutical Science, College of Pharmacy, Sookmyung Women's University, Seoul 04310, Republic of Korea.
| | - Jong-Sun Kang
- Department of Molecular Cell Biology, Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon 16419, Republic of Korea; Samsung Biomedical Research Institute, Samsung Medical Center, Seoul, Republic of Korea.
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Hutton RD, Wilkinson J, Faccin M, Sivertsson EM, Pelizzola A, Lowe AR, Bruscolini P, Itzhaki LS. Mapping the Topography of a Protein Energy Landscape. J Am Chem Soc 2015; 137:14610-25. [PMID: 26561984 DOI: 10.1021/jacs.5b07370] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Protein energy landscapes are highly complex, yet the vast majority of states within them tend to be invisible to experimentalists. Here, using site-directed mutagenesis and exploiting the simplicity of tandem-repeat protein structures, we delineate a network of these states and the routes between them. We show that our target, gankyrin, a 226-residue 7-ankyrin-repeat protein, can access two alternative (un)folding pathways. We resolve intermediates as well as transition states, constituting a comprehensive series of snapshots that map early and late stages of the two pathways and show both to be polarized such that the repeat array progressively unravels from one end of the molecule or the other. Strikingly, we find that the protein folds via one pathway but unfolds via a different one. The origins of this behavior can be rationalized using the numerical results of a simple statistical mechanics model that allows us to visualize the equilibrium behavior as well as single-molecule folding/unfolding trajectories, thereby filling in the gaps that are not accessible to direct experimental observation. Our study highlights the complexity of repeat-protein folding arising from their symmetrical structures; at the same time, however, this structural simplicity enables us to dissect the complexity and thereby map the precise topography of the energy landscape in full breadth and remarkable detail. That we can recapitulate the key features of the folding mechanism by computational analysis of the native structure alone will help toward the ultimate goal of designed amino-acid sequences with made-to-measure folding mechanisms-the Holy Grail of protein folding.
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Affiliation(s)
- Richard D Hutton
- Hutchison/MRC Research Centre , Hills Road, Cambridge CB2 0XZ, U.K
| | - James Wilkinson
- Hutchison/MRC Research Centre , Hills Road, Cambridge CB2 0XZ, U.K
| | - Mauro Faccin
- ICTEAM, Université Catholique de Lovain , Euler Building 4, Avenue Lemaître, B-1348 Louvain-la-Neuve, Belgium
| | - Elin M Sivertsson
- Department of Pharmacology, University of Cambridge , Tennis Court Road, Cambridge CB2 1PD, U.K
| | - Alessandro Pelizzola
- Dipartimento di Scienza Applicata e Tecnologia, CNISM, and Center for Computational Studies, Politecnico di Torino , Corso Duca degli Abruzzi 24, I-10129 Torino, Italy.,INFN, Sezione di Torino , via Pietro Giuria 1, I-10125 Torino, Italy.,Human Genetics Foundation (HuGeF) , Via Nizza 52, I-10126 Torino, Italy
| | - Alan R Lowe
- Institute of Structural and Molecular Biology and London Centre for Nanotechnology, University College London and Birkbeck College , London WC1E 7HX, U.K
| | - Pierpaolo Bruscolini
- Departamento de Física Teórica and Instituto de Biocomputacíon y Física de Sistemas Complejos (BIFI), Universidad de Zaragoza , c/Mariano Esquillor s/n, 50018 Zaragoza, Spain
| | - Laura S Itzhaki
- Department of Pharmacology, University of Cambridge , Tennis Court Road, Cambridge CB2 1PD, U.K
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