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Mumford TR, Rae D, Brackhahn E, Idris A, Gonzalez-Martinez D, Pal AA, Chung MC, Guan J, Rhoades E, Bugaj LJ. Simple visualization of submicroscopic protein clusters with a phase-separation-based fluorescent reporter. Cell Syst 2024; 15:166-179.e7. [PMID: 38335954 PMCID: PMC10947474 DOI: 10.1016/j.cels.2024.01.005] [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: 08/22/2022] [Revised: 11/06/2023] [Accepted: 01/19/2024] [Indexed: 02/12/2024]
Abstract
Protein clustering plays numerous roles in cell physiology and disease. However, protein oligomers can be difficult to detect because they are often too small to appear as puncta in conventional fluorescence microscopy. Here, we describe a fluorescent reporter strategy that detects protein clusters with high sensitivity called CluMPS (clusters magnified by phase separation). A CluMPS reporter detects and visually amplifies even small clusters of a binding partner, generating large, quantifiable fluorescence condensates. We use computational modeling and optogenetic clustering to demonstrate that CluMPS can detect small oligomers and behaves rationally according to key system parameters. CluMPS detected small aggregates of pathological proteins where the corresponding GFP fusions appeared diffuse. CluMPS also detected and tracked clusters of unmodified and tagged endogenous proteins, and orthogonal CluMPS probes could be multiplexed in cells. CluMPS provides a powerful yet straightforward approach to observe higher-order protein assembly in its native cellular context. A record of this paper's transparent peer review process is included in the supplemental information.
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Affiliation(s)
- Thomas R Mumford
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Diarmid Rae
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Emily Brackhahn
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Abbas Idris
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Ayush Aditya Pal
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael C Chung
- Department of Physics, University of Florida, Gainesville, FL 32611, USA
| | - Juan Guan
- Department of Physics, University of Florida, Gainesville, FL 32611, USA; Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL 32611, USA
| | - Elizabeth Rhoades
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lukasz J Bugaj
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA; Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute of Regenerative Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Pal AA, Benman W, Mumford TR, Huang Z, Chow BY, Bugaj LJ. Optogenetic clustering and membrane translocation of the BcLOV4 photoreceptor. Proc Natl Acad Sci U S A 2023; 120:e2221615120. [PMID: 37527339 PMCID: PMC10410727 DOI: 10.1073/pnas.2221615120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [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: 12/20/2022] [Accepted: 06/25/2023] [Indexed: 08/03/2023] Open
Abstract
Optogenetic tools respond to light through one of a small number of behaviors including allosteric changes, dimerization, clustering, or membrane translocation. Here, we describe a new class of optogenetic actuator that simultaneously clusters and translocates to the plasma membrane in response to blue light. We demonstrate that dual translocation and clustering of the BcLOV4 photoreceptor can be harnessed for novel single-component optogenetic tools, including for control of the entire family of epidermal growth factor receptor (ErbB1-4) tyrosine kinases. We further find that clustering and membrane translocation are mechanistically linked. Stronger clustering increased the magnitude of translocation and downstream signaling, increased sensitivity to light by ~threefold-to-fourfold, and decreased the expression levels needed for strong signal activation. Thus light-induced clustering of BcLOV4 provides a strategy to generate a new class of optogenetic tools and to enhance existing ones.
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Affiliation(s)
- Ayush Aditya Pal
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA19104
| | - William Benman
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA19104
| | - Thomas R. Mumford
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA19104
| | - Zikang Huang
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA19104
| | - Brian Y. Chow
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA19104
| | - Lukasz J. Bugaj
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA19104
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA19104
- Institute of Regenerative Medicine, University of Pennsylvania, Philadelphia, PA19104
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