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Fili N, Hari-Gupta Y, Aston B, Dos Santos Á, Gough RE, Alamad B, Wang L, Martin-Fernandez ML, Toseland CP. Competition between two high- and low-affinity protein-binding sites in myosin VI controls its cellular function. J Biol Chem 2019; 295:337-347. [PMID: 31744880 DOI: 10.1074/jbc.ra119.010142] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 11/15/2019] [Indexed: 11/06/2022] Open
Abstract
Myosin VI is involved in many cellular processes ranging from endocytosis to transcription. This multifunctional potential is achieved through alternative isoform splicing and through interactions of myosin VI with a diverse network of binding partners. However, the interplay between these two modes of regulation remains unexplored. To this end, we compared two different binding partners and their interactions with myosin VI by exploring the kinetic properties of recombinant proteins and their distribution in mammalian cells using fluorescence imaging. We found that selectivity for these binding partners is achieved through a high-affinity motif and a low-affinity motif within myosin VI. These two motifs allow competition among partners for myosin VI. Exploring how this competition affects the activity of nuclear myosin VI, we demonstrate the impact of a concentration-driven interaction with the low-affinity binding partner DAB2, finding that this interaction blocks the ability of nuclear myosin VI to bind DNA and its transcriptional activity in vitro We conclude that loss of DAB2, a tumor suppressor, may enhance myosin VI-mediated transcription. We propose that the frequent loss of specific myosin VI partner proteins during the onset of cancer leads to a higher level of nuclear myosin VI activity.
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Affiliation(s)
- Natalia Fili
- Sheffield Cancer Centre, Department of Oncology and Metabolism, University of Sheffield, Sheffield S10 2RX, United Kingdom
| | - Yukti Hari-Gupta
- School of Biosciences, University of Kent, Canterbury CT2 7NZ, United Kingdom
| | - Bjork Aston
- School of Biosciences, University of Kent, Canterbury CT2 7NZ, United Kingdom
| | - Ália Dos Santos
- Sheffield Cancer Centre, Department of Oncology and Metabolism, University of Sheffield, Sheffield S10 2RX, United Kingdom
| | - Rosemarie E Gough
- Sheffield Cancer Centre, Department of Oncology and Metabolism, University of Sheffield, Sheffield S10 2RX, United Kingdom
| | - Bana Alamad
- School of Biosciences, University of Kent, Canterbury CT2 7NZ, United Kingdom
| | - Lin Wang
- Central Laser Facility, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Didcot, Oxford OX11 0QX, United Kingdom
| | - Marisa L Martin-Fernandez
- Central Laser Facility, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Didcot, Oxford OX11 0QX, United Kingdom
| | - Christopher P Toseland
- Sheffield Cancer Centre, Department of Oncology and Metabolism, University of Sheffield, Sheffield S10 2RX, United Kingdom.
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Fili N, Hari-Gupta Y, Dos Santos Á, Cook A, Poland S, Ameer-Beg SM, Parsons M, Toseland CP. NDP52 activates nuclear myosin VI to enhance RNA polymerase II transcription. Nat Commun 2017; 8:1871. [PMID: 29187741 PMCID: PMC5707354 DOI: 10.1038/s41467-017-02050-w] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 10/30/2017] [Indexed: 11/09/2022] Open
Abstract
Myosin VI (MVI) has been found to be overexpressed in ovarian, breast and prostate cancers. Moreover, it has been shown to play a role in regulating cell proliferation and migration, and to interact with RNA Polymerase II (RNAPII). Here, we find that backfolding of MVI regulates its ability to bind DNA and that a putative transcription co-activator NDP52 relieves the auto-inhibition of MVI to enable DNA binding. Additionally, we show that the MVI-NDP52 complex binds RNAPII, which is critical for transcription, and that depletion of NDP52 or MVI reduces steady-state mRNA levels. Lastly, we demonstrate that MVI directly interacts with nuclear receptors to drive expression of target genes, thereby suggesting a link to cell proliferation and migration. Overall, we suggest MVI may function as an auxiliary motor to drive transcription.
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Affiliation(s)
- Natalia Fili
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | - Yukti Hari-Gupta
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | - Ália Dos Santos
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | - Alexander Cook
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | - Simon Poland
- Randall Division of Cell and Molecular Biophysics, King's College London, Guys Campus, London, SE1 1UL, UK
| | - Simon M Ameer-Beg
- Randall Division of Cell and Molecular Biophysics, King's College London, Guys Campus, London, SE1 1UL, UK
| | - Maddy Parsons
- Randall Division of Cell and Molecular Biophysics, King's College London, Guys Campus, London, SE1 1UL, UK
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