1
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Zhao X, Quintremil S, Rodriguez Castro ED, Cui H, Moraga D, Wang T, Vallee RB, Solmaz SR. Molecular mechanism for recognition of the cargo adapter Rab6 GTP by the dynein adapter BicD2. Life Sci Alliance 2024; 7:e202302430. [PMID: 38719748 PMCID: PMC11077774 DOI: 10.26508/lsa.202302430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/12/2024] Open
Abstract
Rab6 is a key modulator of protein secretion. The dynein adapter Bicaudal D2 (BicD2) recruits the motors cytoplasmic dynein and kinesin-1 to Rab6GTP-positive vesicles for transport; however, it is unknown how BicD2 recognizes Rab6. Here, we establish a structural model for recognition of Rab6GTP by BicD2, using structure prediction and mutagenesis. The binding site of BicD2 spans two regions of Rab6 that undergo structural changes upon the transition from the GDP- to GTP-bound state, and several hydrophobic interface residues are rearranged, explaining the increased affinity of the active GTP-bound state. Mutations of Rab6GTP that abolish binding to BicD2 also result in reduced co-migration of Rab6GTP/BicD2 in cells, validating our model. These mutations also severely diminished the motility of Rab6-positive vesicles in cells, highlighting the importance of the Rab6GTP/BicD2 interaction for overall motility of the multi-motor complex that contains both kinesin-1 and dynein. Our results provide insights into trafficking of secretory and Golgi-derived vesicles and will help devise therapies for diseases caused by BicD2 mutations, which selectively affect the affinity to Rab6 and other cargoes.
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Affiliation(s)
- Xiaoxin Zhao
- https://ror.org/008rmbt77 Department of Chemistry, Binghamton University, Binghamton, NY, USA
| | - Sebastian Quintremil
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | | | - Heying Cui
- https://ror.org/008rmbt77 Department of Chemistry, Binghamton University, Binghamton, NY, USA
| | - David Moraga
- https://ror.org/008rmbt77 Department of Chemistry, Binghamton University, Binghamton, NY, USA
| | - Tingyao Wang
- https://ror.org/008rmbt77 Department of Chemistry, Binghamton University, Binghamton, NY, USA
| | - Richard B Vallee
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Sozanne R Solmaz
- https://ror.org/008rmbt77 Department of Chemistry, Binghamton University, Binghamton, NY, USA
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2
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Gibson JM, Zhao X, Ali MY, Solmaz SR, Wang C. A Structural Model for the Core Nup358-BicD2 Interface. Biomolecules 2023; 13:1445. [PMID: 37892127 PMCID: PMC10604712 DOI: 10.3390/biom13101445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 09/08/2023] [Accepted: 09/19/2023] [Indexed: 10/29/2023] Open
Abstract
Dynein motors facilitate the majority of minus-end-directed transport events on microtubules. The dynein adaptor Bicaudal D2 (BicD2) recruits the dynein machinery to several cellular cargo for transport, including Nup358, which facilitates a nuclear positioning pathway that is essential for the differentiation of distinct brain progenitor cells. Previously, we showed that Nup358 forms a "cargo recognition α-helix" upon binding to BicD2; however, the specifics of the BicD2-Nup358 interface are still not well understood. Here, we used AlphaFold2, complemented by two additional docking programs (HADDOCK and ClusPro) as well as mutagenesis, to show that the Nup358 cargo-recognition α-helix binds to BicD2 between residues 747 and 774 in an anti-parallel manner, forming a helical bundle. We identified two intermolecular salt bridges that are important to stabilize the interface. In addition, we uncovered a secondary interface mediated by an intrinsically disordered region of Nup358 that is directly N-terminal to the cargo-recognition α-helix and binds to BicD2 between residues 774 and 800. This is the same BicD2 domain that binds to the competing cargo adapter Rab6, which is important for the transport of Golgi-derived and secretory vesicles. Our results establish a structural basis for cargo recognition and selection by the dynein adapter BicD2, which facilitates transport pathways that are important for brain development.
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Affiliation(s)
- James M. Gibson
- Department of Biological Sciences, Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
| | - Xiaoxin Zhao
- Department of Chemistry, Binghamton University, P.O. Box 6000, Binghamton, NY 13902, USA;
| | - M. Yusuf Ali
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT 05405, USA;
| | - Sozanne R. Solmaz
- Department of Chemistry, Binghamton University, P.O. Box 6000, Binghamton, NY 13902, USA;
| | - Chunyu Wang
- Department of Biological Sciences, Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA
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3
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Yi J, Zhao X, Noell CR, Helmer P, Solmaz SR, Vallee RB. Role of Nesprin-2 and RanBP2 in BICD2-associated brain developmental disorders. PLoS Genet 2023; 19:e1010642. [PMID: 36930595 PMCID: PMC10022797 DOI: 10.1371/journal.pgen.1010642] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 01/28/2023] [Indexed: 03/18/2023] Open
Abstract
Bicaudal D2 (BICD2) is responsible for recruiting cytoplasmic dynein to diverse forms of subcellular cargo for their intracellular transport. Mutations in the human BICD2 gene have been found to cause an autosomal dominant form of spinal muscular atrophy (SMA-LED2), and brain developmental defects. Whether and how the latter mutations are related to roles we and others have identified for BICD2 in brain development remains little understood. BICD2 interacts with the nucleoporin RanBP2 to recruit dynein to the nuclear envelope (NE) of Radial Glial Progenitor cells (RGPs) to mediate their well-known but mysterious cell-cycle-regulated interkinetic nuclear migration (INM) behavior, and their subsequent differentiation to form cortical neurons. We more recently found that BICD2 also mediates NE dynein recruitment in migrating post-mitotic neurons, though via a different interactor, Nesprin-2. Here, we report that Nesprin-2 and RanBP2 compete for BICD2-binding in vitro. To test the physiological implications of this behavior, we examined the effects of known BICD2 mutations using in vitro biochemical and in vivo electroporation-mediated brain developmental assays. We find a clear relationship between the ability of BICD2 to bind RanBP2 vs. Nesprin-2 in controlling of nuclear migration and neuronal migration behavior. We propose that mutually exclusive RanBP2-BICD2 vs. Nesprin-2-BICD2 interactions at the NE play successive, critical roles in INM behavior in RGPs and in post-mitotic neuronal migration and errors in these processes contribute to specific human brain malformations.
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Affiliation(s)
- Julie Yi
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
| | - Xiaoxin Zhao
- Department of Chemistry, Binghamton University, Binghamton, New York, New York, United States of America
| | - Crystal R. Noell
- Department of Chemistry, Binghamton University, Binghamton, New York, New York, United States of America
| | - Paige Helmer
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
| | - Sozanne R. Solmaz
- Department of Chemistry, Binghamton University, Binghamton, New York, New York, United States of America
| | - Richard B. Vallee
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
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4
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Wang T, Zhao X, Cui H, Moraga DL, Solmaz SR. Biophysical characterization of Rab6 mutants that are important for the interaction with the dynein adaptor BicD2. Biophys J 2023; 122:411a. [PMID: 36784100 DOI: 10.1016/j.bpj.2022.11.2234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Tingyao Wang
- State University of New York Binghamton University, Binghamton, NY, USA
| | - Xiaoxin Zhao
- State University of New York Binghamton University, Binghamton, NY, USA
| | - Heying Cui
- State University of New York Binghamton University, Binghamton, NY, USA
| | - David L Moraga
- State University of New York Binghamton University, Binghamton, NY, USA
| | - Sozanne R Solmaz
- State University of New York Binghamton University, Binghamton, NY, USA
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5
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Zhao X, Cui H, Moraga D, Wang T, Solmaz SR. Recognition of Rab6 by the dynein adaptor BicD2. Biophys J 2023; 122:411a. [PMID: 36784099 DOI: 10.1016/j.bpj.2022.11.2235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Xiaoxin Zhao
- Chemistry, State University of New York Binghamton University, Binghamton, NY, USA
| | - Heying Cui
- Chemistry, State University of New York Binghamton University, Binghamton, NY, USA
| | | | - Tingyao Wang
- Chemistry, State University of New York Binghamton University, Binghamton, NY, USA
| | - Sozanne R Solmaz
- Chemistry, State University of New York Binghamton University, Binghamton, NY, USA
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6
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Gibson JM, Cui H, Ali MY, Zhao X, Debler EW, Zhao J, Trybus KM, Solmaz SR, Wang C. Coil-to-α-helix transition at the Nup358-BicD2 interface activates BicD2 for dynein recruitment. eLife 2022; 11:74714. [PMID: 35229716 PMCID: PMC8956292 DOI: 10.7554/elife.74714] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 02/28/2022] [Indexed: 11/13/2022] Open
Abstract
Nup358, a protein of the nuclear pore complex, facilitates a nuclear positioning pathway that is essential for many biological processes, including neuromuscular and brain development. Nup358 interacts with the dynein adaptor Bicaudal D2 (BicD2), which in turn recruits the dynein machinery to position the nucleus. However, the molecular mechanisms of the Nup358/BicD2 interaction and the activation of transport remain poorly understood. Here for the first time, we show that a minimal Nup358 domain activates dynein/dynactin/BicD2 for processive motility on microtubules. Using nuclear magnetic resonance titration and chemical exchange saturation transfer, mutagenesis, and circular dichroism spectroscopy, a Nup358 α-helix encompassing residues 2162–2184 was identified, which transitioned from a random coil to an α-helical conformation upon BicD2 binding and formed the core of the Nup358-BicD2 interface. Mutations in this region of Nup358 decreased the Nup358/BicD2 interaction, resulting in decreased dynein recruitment and impaired motility. BicD2 thus recognizes Nup358 through a ‘cargo recognition α-helix,’ a structural feature that may stabilize BicD2 in its activated state and promote processive dynein motility.
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Affiliation(s)
- James M Gibson
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, United States
| | - Heying Cui
- Department of Chemistry, Binghamton University, Binghamton, United States
| | - M Yusuf Ali
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, United States
| | - Xioaxin Zhao
- Department of Biological Sciences, Binghamton University, Binghamton, United States
| | - Erik W Debler
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, United States
| | - Jing Zhao
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, United States
| | - Kathleen M Trybus
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, United States
| | - Sozanne R Solmaz
- Department of Chemistry, Binghamton University, Binghamton, United States
| | - Chunyu Wang
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, United States
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7
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Cui H, Ali MY, Goyal P, Zhang K, Loh JY, Trybus KM, Solmaz SR. Coiled-coil registry shifts in the F684I mutant of Bicaudal D result in cargo-independent activation of dynein motility. Traffic 2021; 21:463-478. [PMID: 32378283 DOI: 10.1111/tra.12734] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 04/29/2020] [Accepted: 05/01/2020] [Indexed: 11/28/2022]
Abstract
The dynein adaptor Drosophila Bicaudal D (BicD) is auto-inhibited and activates dynein motility only after cargo is bound, but the underlying mechanism is elusive. In contrast, we show that the full-length BicD/F684I mutant activates dynein processivity even in the absence of cargo. Our X-ray structure of the C-terminal domain of the BicD/F684I mutant reveals a coiled-coil registry shift; in the N-terminal region, the two helices of the homodimer are aligned, whereas they are vertically shifted in the wild-type. One chain is partially disordered and this structural flexibility is confirmed by computations, which reveal that the mutant transitions back and forth between the two registries. We propose that a coiled-coil registry shift upon cargo-binding activates BicD for dynein recruitment. Moreover, the human homolog BicD2/F743I exhibits diminished binding of cargo adaptor Nup358, implying that a coiled-coil registry shift may be a mechanism to modulate cargo selection for BicD2-dependent transport pathways.
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Affiliation(s)
- Heying Cui
- Department of Chemistry, State University of New York at Binghamton, Binghamton, New York, USA
| | - M Yusuf Ali
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont, USA
| | - Puja Goyal
- Department of Chemistry, State University of New York at Binghamton, Binghamton, New York, USA
| | - Kaiqi Zhang
- Department of Chemistry, State University of New York at Binghamton, Binghamton, New York, USA
| | - Jia Ying Loh
- Department of Chemistry, State University of New York at Binghamton, Binghamton, New York, USA
| | - Kathleen M Trybus
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont, USA
| | - Sozanne R Solmaz
- Department of Chemistry, State University of New York at Binghamton, Binghamton, New York, USA
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8
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Zhao J, Blayney A, Liu X, Gandy L, Jin W, Yan L, Ha JH, Canning AJ, Connelly M, Yang C, Liu X, Xiao Y, Cosgrove MS, Solmaz SR, Zhang Y, Ban D, Chen J, Loh SN, Wang C. EGCG binds intrinsically disordered N-terminal domain of p53 and disrupts p53-MDM2 interaction. Nat Commun 2021; 12:986. [PMID: 33579943 PMCID: PMC7881117 DOI: 10.1038/s41467-021-21258-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 01/11/2021] [Indexed: 12/19/2022] Open
Abstract
Epigallocatechin gallate (EGCG) from green tea can induce apoptosis in cancerous cells, but the underlying molecular mechanisms remain poorly understood. Using SPR and NMR, here we report a direct, μM interaction between EGCG and the tumor suppressor p53 (KD = 1.6 ± 1.4 μM), with the disordered N-terminal domain (NTD) identified as the major binding site (KD = 4 ± 2 μM). Large scale atomistic simulations (>100 μs), SAXS and AUC demonstrate that EGCG-NTD interaction is dynamic and EGCG causes the emergence of a subpopulation of compact bound conformations. The EGCG-p53 interaction disrupts p53 interaction with its regulatory E3 ligase MDM2 and inhibits ubiquitination of p53 by MDM2 in an in vitro ubiquitination assay, likely stabilizing p53 for anti-tumor activity. Our work provides insights into the mechanisms for EGCG's anticancer activity and identifies p53 NTD as a target for cancer drug discovery through dynamic interactions with small molecules.
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Affiliation(s)
- Jing Zhao
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
- Center for Biotechnology and Interdisciplinary Studies, Department of Chemistry and Chemical Biology, Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Alan Blayney
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Xiaorong Liu
- Department of Chemistry, University of Massachusetts, Amherst, MA, USA
| | - Lauren Gandy
- Center for Biotechnology and Interdisciplinary Studies, Department of Chemistry and Chemical Biology, Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Weihua Jin
- Center for Biotechnology and Interdisciplinary Studies, Department of Chemistry and Chemical Biology, Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Lufeng Yan
- Center for Biotechnology and Interdisciplinary Studies, Department of Chemistry and Chemical Biology, Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Jeung-Hoi Ha
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Ashley J Canning
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Michael Connelly
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Chao Yang
- Department of Chemistry, New York University, New York, NY, USA
| | - Xinyue Liu
- Center for Biotechnology and Interdisciplinary Studies, Department of Chemistry and Chemical Biology, Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Yuanyuan Xiao
- Center for Biotechnology and Interdisciplinary Studies, Department of Chemistry and Chemical Biology, Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Michael S Cosgrove
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Sozanne R Solmaz
- Department of Chemistry, State University of New York at Binghamton, Binghamton, NY, USA
| | - Yingkai Zhang
- Department of Chemistry, New York University, New York, NY, USA
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai, China
| | - David Ban
- Merck Research Laboratories, Mass Spectrometry and Biophysics, Kenilworth, NJ, USA
| | - Jianhan Chen
- Department of Chemistry, University of Massachusetts, Amherst, MA, USA
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA, USA
| | - Stewart N Loh
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Chunyu Wang
- Center for Biotechnology and Interdisciplinary Studies, Department of Chemistry and Chemical Biology, Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY, USA.
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9
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Cui H, Ali MY, Goyal P, Zhang K, Ying Loh J, Trybus KM, Solmaz SR. Dynein Adaptors Such as Drosophila Bicaudal (Dm BicD) Recognize Cargo and are Required to Activate Dynein for Processive Transport. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.1890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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10
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Noell CR, Cui H, Behler R, Zahn J, Terry L, Russ B, Solmaz SR. Adaptor Proteins for Opposing Motors Interact Simultaneously to Nuclear Pore Protein Nup358. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.1180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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11
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Moraga DL, Solmaz SR. Identification of Interface Residues of the Rab6/BicD2 Complex. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.1174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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12
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Cui H, Ali MY, Goyal P, Zhang K, Loh JY, Trybus KM, Solmaz SR. Coiled-Coil Registry Shifts in the F684I Mutant of Bicaudal D Result in Cargo-Independent Activation of Dynein Motility. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.1170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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13
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Cui H, Trybus KM, Ali MY, Goyal P, Aura XD, Loh JY, Noell CR, Solmaz SR. Coiled-Coil Registry Shifts in the F684I Mutant of Bicaudal Result in Cargo-Independent Activation of Dynein Motility. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.2407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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14
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Cui H, Noell CR, Behler RP, Zahn JB, Terry LR, Russ BB, Solmaz SR. Adapter Proteins for Opposing Motors Interact Simultaneously with Nuclear Pore Protein Nup358. Biochemistry 2019; 58:5085-5097. [PMID: 31756096 DOI: 10.1021/acs.biochem.9b00907] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Nup358 is a protein subunit of the nuclear pore complex that recruits the opposing microtubule motors kinesin-1 and dynein [via the dynein adaptor Bicaudal D2 (BicD2)] to the nuclear envelope. This pathway is important for positioning of the nucleus during the early steps of mitotic spindle assembly and also essential for an important process in brain development. It is unknown whether dynein and kinesin-1 interact with Nup358 simultaneously or whether they compete. Here, we have reconstituted and characterized a minimal complex of kinesin-1 light chain 2 (KLC2) and Nup358. The proteins interact through a W-acidic motif in Nup358, which is highly conserved among vertebrates but absent in insects. While Nup358 and KLC2 form predominantly monomers, their interaction results in the formation of 2:2 complexes, and the W-acidic motif is required for the oligomerization. In active motor complexes, BicD2 and KLC2 each form dimers. Notably, we show that the dynein adaptor BicD2 and KLC2 interact simultaneously with Nup358, resulting in the formation of 2:2:2 complexes. Mutation of the W-acidic motif results in the formation of 1:1:1 complexes. On the basis of our data, we propose that Nup358 recruits simultaneously one kinesin-1 motor and one dynein motor via BicD2 to the nucleus. We hypothesize that the binding sites are close enough to promote direct interactions between these motor recognition domains, which may be important for the regulation of the motility of these opposing motors. Our data provide important insights into a nuclear positioning pathway that is crucial for brain development and faithful chromosome segregation.
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Affiliation(s)
- Heying Cui
- Department of Chemistry , Binghamton University , P.O. Box 6000, Binghamton , New York 13902 , United States
| | - Crystal R Noell
- Department of Chemistry , Binghamton University , P.O. Box 6000, Binghamton , New York 13902 , United States
| | - Rachael P Behler
- Department of Chemistry , Binghamton University , P.O. Box 6000, Binghamton , New York 13902 , United States
| | - Jacqueline B Zahn
- Department of Chemistry , Binghamton University , P.O. Box 6000, Binghamton , New York 13902 , United States
| | - Lynn R Terry
- Department of Chemistry , Binghamton University , P.O. Box 6000, Binghamton , New York 13902 , United States
| | - Blaine B Russ
- Department of Chemistry , Binghamton University , P.O. Box 6000, Binghamton , New York 13902 , United States
| | - Sozanne R Solmaz
- Department of Chemistry , Binghamton University , P.O. Box 6000, Binghamton , New York 13902 , United States
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15
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Noell CR, Loh JY, Debler EW, Loftus KM, Cui H, Russ BB, Zhang K, Goyal P, Solmaz SR. Role of Coiled-Coil Registry Shifts in the Activation of Human Bicaudal D2 for Dynein Recruitment upon Cargo Binding. J Phys Chem Lett 2019; 10:4362-4367. [PMID: 31306018 PMCID: PMC7243283 DOI: 10.1021/acs.jpclett.9b01865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Dynein adaptors such as Bicaudal D2 (BicD2) recognize cargo for dynein-dependent transport, and cargo-bound adaptors are required to activate dynein for processive transport, but the mechanism of action is unknown. Here we report the X-ray structure of the cargo-binding domain of human BicD2 and investigate the structural dynamics of the coiled-coil. Our molecular dynamics simulations support the fact that BicD2 can switch from a homotypic coiled-coil registry, in which both helices of the homodimer are aligned, to an asymmetric registry, where a portion of one helix is vertically shifted, as both states are similarly stable and defined by distinct conformations of F743. The F743I variant increases dynein recruitment in the Drosophila homologue, whereas the human R747C variant causes spinal muscular atrophy. We report spontaneous registry shifts for both variants, which may be the cause for BicD2 hyperactivation and disease. We propose that a registry shift upon cargo binding may activate autoinhibited BicD2 for dynein recruitment.
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Affiliation(s)
- Crystal R. Noell
- Department of Chemistry, State University of New York at Binghamton, P.O. Box 6000, Binghamton, New York 13902, United States
| | - Jia Ying Loh
- Department of Chemistry, State University of New York at Binghamton, P.O. Box 6000, Binghamton, New York 13902, United States
| | - Erik W. Debler
- Department of Biochemistry & Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, Pennsylvania 19107, United States
| | - Kyle M. Loftus
- Department of Chemistry, State University of New York at Binghamton, P.O. Box 6000, Binghamton, New York 13902, United States
| | - Heying Cui
- Department of Chemistry, State University of New York at Binghamton, P.O. Box 6000, Binghamton, New York 13902, United States
| | - Blaine B. Russ
- Department of Chemistry, State University of New York at Binghamton, P.O. Box 6000, Binghamton, New York 13902, United States
| | - Kaiqi Zhang
- Department of Chemistry, State University of New York at Binghamton, P.O. Box 6000, Binghamton, New York 13902, United States
| | - Puja Goyal
- Department of Chemistry, State University of New York at Binghamton, P.O. Box 6000, Binghamton, New York 13902, United States
- Corresponding Authors:. Tel: +1 607 777 4308 (P.G.)., . Tel: +1 607 777 2089 (S.R.S.)
| | - Sozanne R. Solmaz
- Department of Chemistry, State University of New York at Binghamton, P.O. Box 6000, Binghamton, New York 13902, United States
- Corresponding Authors:. Tel: +1 607 777 4308 (P.G.)., . Tel: +1 607 777 2089 (S.R.S.)
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16
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Abstract
Dynein adaptor proteins such as Bicaudal D2 (BicD2) are integral components of the dynein transport machinery, as they recognize cargoes for cell cycle-specific transport and link them to the motor complex. Human BicD2 switches from selecting secretory and Golgi-derived vesicles for transport in G1 and S phase (by recognizing Rab6GTP), to selecting the nucleus for transport in G2 phase (by recognizing nuclear pore protein Nup358), but the molecular mechanisms governing this switch are elusive. Here, we have developed a quantitative model for BicD2/cargo interactions that integrates affinities, oligomeric states, and cellular concentrations of the reactants. BicD2 and cargo form predominantly 2:2 complexes. Furthermore, the affinity of BicD2 toward its cargo Nup358 is higher than that toward Rab6GTP. Based on our calculations, an estimated 1000 BicD2 molecules per cell would be recruited to the nucleus through Nup358 in the absence of regulation. Notably, RanGTP is a negative regulator of the Nup358/BicD2 interaction that weakens the affinity by a factor of 10 and may play a role in averting dynein recruitment to the nucleus outside of the G2 phase. However, our quantitative model predicts that an additional negative regulator remains to be identified. In the absence of negative regulation, the affinity of Nup358 would likely be sufficient to recruit BicD2 to the nucleus in G2 phase. Our quantitative model makes testable predictions of how cellular transport events are orchestrated. These transport processes are important for brain development, cell cycle control, signaling, and neurotransmission at synapses.
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Affiliation(s)
- Crystal R Noell
- Department of Chemistry , State University of New York at Binghamton , Binghamton , New York 13902 , United States
| | - Kyle M Loftus
- Department of Chemistry , State University of New York at Binghamton , Binghamton , New York 13902 , United States
| | - Heying Cui
- Department of Chemistry , State University of New York at Binghamton , Binghamton , New York 13902 , United States
| | - Christof Grewer
- Department of Chemistry , State University of New York at Binghamton , Binghamton , New York 13902 , United States
| | - Megan Kizer
- Department of Chemistry , State University of New York at Binghamton , Binghamton , New York 13902 , United States
| | - Erik W Debler
- Department of Biochemistry & Molecular Biology , Thomas Jefferson University , Philadelphia , Pennsylvania 19107 , United States
| | - Sozanne R Solmaz
- Department of Chemistry , State University of New York at Binghamton , Binghamton , New York 13902 , United States
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17
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Cui H, Loftus KM, Noell CR, Solmaz SR. Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay. J Vis Exp 2018. [PMID: 29782014 DOI: 10.3791/57674] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Cyclin-dependent kinase 1 (Cdk1) is a master controller for the cell cycle in all eukaryotes and phosphorylates an estimated 8 - 13% of the proteome; however, the number of identified targets for Cdk1, particularly in human cells is still low. The identification of Cdk1-specific phosphorylation sites is important, as they provide mechanistic insights into how Cdk1 controls the cell cycle. Cell cycle regulation is critical for faithful chromosome segregation, and defects in this complicated process lead to chromosomal aberrations and cancer. Here, we describe an in vitro kinase assay that is used to identify Cdk1-specific phosphorylation sites. In this assay, a purified protein is phosphorylated in vitro by commercially available human Cdk1/cyclin B. Successful phosphorylation is confirmed by SDS-PAGE, and phosphorylation sites are subsequently identified by mass spectrometry. We also describe purification protocols that yield highly pure and homogeneous protein preparations suitable for the kinase assay, and a binding assay for the functional verification of the identified phosphorylation sites, which probes the interaction between a classical nuclear localization signal (cNLS) and its nuclear transport receptor karyopherin α. To aid with experimental design, we review approaches for the prediction of Cdk1-specific phosphorylation sites from protein sequences. Together these protocols present a very powerful approach that yields Cdk1-specific phosphorylation sites and enables mechanistic studies into how Cdk1 controls the cell cycle. Since this method relies on purified proteins, it can be applied to any model organism and yields reliable results, especially when combined with cell functional studies.
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Affiliation(s)
- Heying Cui
- Department of Chemistry, State University of New York at Binghamton
| | - Kyle M Loftus
- Department of Chemistry, State University of New York at Binghamton
| | - Crystal R Noell
- Department of Chemistry, State University of New York at Binghamton
| | - Sozanne R Solmaz
- Department of Chemistry, State University of New York at Binghamton;
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18
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Loftus KM, Cui H, Coutavas E, King DS, Ceravolo A, Pereiras D, Solmaz SR. Mechanism for G2 phase-specific nuclear export of the kinetochore protein CENP-F. Cell Cycle 2017; 16:1414-1429. [PMID: 28723232 DOI: 10.1080/15384101.2017.1338218] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Centromere protein F (CENP-F) is a component of the kinetochore and a regulator of cell cycle progression. CENP-F recruits the dynein transport machinery and orchestrates several cell cycle-specific transport events, including transport of the nucleus, mitochondria and chromosomes. A key regulatory step for several of these functions is likely the G2 phase-specific export of CENP-F from the nucleus to the cytosol, where the cytoplasmic dynein transport machinery resides; however, the molecular mechanism of this process is elusive. Here, we have identified 3 phosphorylation sites within the bipartite classical nuclear localization signal (cNLS) of CENP-F. These sites are specific for cyclin-dependent kinase 1 (Cdk1), which is active in G2 phase. Phosphomimetic mutations of these residues strongly diminish the interaction of the CENP-F cNLS with its nuclear transport receptor karyopherin α. These mutations also diminish nuclear localization of the CENP-F cNLS in cells. Notably, the cNLS is phosphorylated in the -1 position, which is important to orient the adjacent major motif for binding into its pocket on karyopherin α. We propose that localization of CENP-F is regulated by a cNLS, and a nuclear export pathway, resulting in nuclear localization during most of interphase. In G2 phase, the cNLS is weakened by phosphorylation through Cdk1, likely resulting in nuclear export of CENP-F via the still active nuclear export pathway. Once CENP-F resides in the cytosol, it can engage in pathways that are important for cell cycle progression, kinetochore assembly and the faithful segregation of chromosomes into daughter cells.
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Affiliation(s)
- Kyle M Loftus
- a Department of Chemistry , State University of New York at Binghamton , New York , NY , USA
| | - Heying Cui
- a Department of Chemistry , State University of New York at Binghamton , New York , NY , USA
| | - Elias Coutavas
- b Laboratory of Cell Biology , The Rockefeller University , New York , NY , USA
| | - David S King
- c Howard Hughes Medical Institute, Mass Spectrometry Laboratory , University of California at Berkeley , Berkeley , CA , USA
| | - Amanda Ceravolo
- a Department of Chemistry , State University of New York at Binghamton , New York , NY , USA
| | - Dylan Pereiras
- a Department of Chemistry , State University of New York at Binghamton , New York , NY , USA
| | - Sozanne R Solmaz
- a Department of Chemistry , State University of New York at Binghamton , New York , NY , USA
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19
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Sharma A, Solmaz SR, Blobel G, Melčák I. Ordered Regions of Channel Nucleoporins Nup62, Nup54, and Nup58 Form Dynamic Complexes in Solution. J Biol Chem 2015; 290:18370-8. [PMID: 26025361 PMCID: PMC4513098 DOI: 10.1074/jbc.m115.663500] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Indexed: 11/16/2022] Open
Abstract
Three out of ∼30 nucleoporins, Nup62, Nup54, and Nup58, line the nuclear pore channel. These “channel” nucleoporins each contain an ordered region of ∼150–200 residues, which is predicted to be segmented into 3–4 α-helical regions of ∼40–80 residues. Notably, these segmentations are evolutionarily conserved between uni- and multicellular eukaryotes. Strikingly, the boundaries of these segments match our previously reported mapping and crystal data, which collectively identified two “cognate” segments of Nup54, each interacting with cognate segments, one in Nup58 and the other one in Nup62. Because Nup54 and Nup58 cognate segments form crystallographic hetero- or homo-oligomers, we proposed that these oligomers associate into inter-convertible “mid-plane” rings: a single large ring (40–50 nm diameter, consisting of eight hetero-dodecamers) or three small rings (10–20 nm diameter, each comprising eight homo-tetramers). Each “ring cycle” would recapitulate “dilation” and “constriction” of the nuclear pore complex's central transport channel. As for the Nup54·Nup62 interactome, it forms a 1:2 triple helix (“finger”), multiples of which project alternately up and down from mid-plane ring(s). Collectively, our previous crystal data suggested a copy number of 128, 64, and 32 for Nup62, Nup54, and Nup58, respectively, that is, a 4:2:1 stoichiometry. Here, we carried out solution analysis utilizing the entire ordered regions of Nup62, Nup54, and Nup58, and demonstrate that they form a dynamic “triple complex” that is heterogeneously formed from our previously characterized Nup54·Nup58 and Nup54·Nup62 interactomes. These data are consistent both with our crystal structure-deduced copy numbers and stoichiometries and also with our ring cycle model for structure and dynamics of the nuclear pore channel.
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Affiliation(s)
- Alok Sharma
- From the Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, New York 10065
| | - Sozanne R Solmaz
- From the Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, New York 10065
| | - Günter Blobel
- From the Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, New York 10065
| | - Ivo Melčák
- From the Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, New York 10065
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20
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Solmaz SR, Chauhan R, Blobel G, Melčák I. Molecular architecture of the transport channel of the nuclear pore complex. Cell 2011; 147:590-602. [PMID: 22036567 PMCID: PMC3431207 DOI: 10.1016/j.cell.2011.09.034] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Revised: 06/28/2011] [Accepted: 09/12/2011] [Indexed: 01/02/2023]
Abstract
The nuclear pore complex encloses a central channel for nucleocytoplasmic transport, which is thought to consist of three nucleoporins, Nup54, Nup58, and Nup62. However, the structure and composition of the channel are elusive. We determined the crystal structures of the interacting domains between these nucleoporins and pieced together the molecular architecture of the mammalian transport channel. Located in the channel midplane is a flexible Nup54⋅Nup58 ring that can undergo large rearrangements yielding diameter changes from ∼20 to ∼40 nm. Nup62⋅Nup54 triple helices project alternately up and down from either side of the midplane ring and form nucleoplasmic and cytoplasmic entries. The channel consists of as many as 224 copies of the three nucleoporins, amounting to a molar mass of 12.3 MDa and contributing 256 phenylalanine-glycine repeat regions. We propose that the occupancy of these repeat regions with transport receptors modulates ring diameter and transport activity.
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Affiliation(s)
- Sozanne R Solmaz
- Laboratory of Cell Biology, Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
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