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Absmeier RM, Rottenaicher GJ, Svilenov HL, Kazman P, Buchner J. Antibodies gone bad - the molecular mechanism of light chain amyloidosis. FEBS J 2023; 290:1398-1419. [PMID: 35122394 DOI: 10.1111/febs.16390] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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: 11/25/2021] [Revised: 01/19/2022] [Accepted: 02/03/2022] [Indexed: 12/19/2022]
Abstract
Light chain amyloidosis (AL) is a systemic disease in which abnormally proliferating plasma cells secrete large amounts of mutated antibody light chains (LCs) that eventually form fibrils. The fibrils are deposited in various organs, most often in the heart and kidney, and impair their function. The prognosis for patients diagnosed with AL is generally poor. The disease is set apart from other amyloidoses by the huge number of patient-specific mutations in the disease-causing and fibril-forming protein. The molecular mechanisms that drive the aggregation of mutated LCs into fibrils have been enigmatic, which hindered the development of efficient diagnostics and therapies. In this review, we summarize our current knowledge on AL amyloidosis and discuss open issues.
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Affiliation(s)
- Ramona M Absmeier
- Center for Functional Protein Assemblies and Department of Chemistry, Technische Universität München, Garching, Germany
| | - Georg J Rottenaicher
- Center for Functional Protein Assemblies and Department of Chemistry, Technische Universität München, Garching, Germany
| | - Hristo L Svilenov
- Center for Functional Protein Assemblies and Department of Chemistry, Technische Universität München, Garching, Germany
| | - Pamina Kazman
- Center for Functional Protein Assemblies and Department of Chemistry, Technische Universität München, Garching, Germany
| | - Johannes Buchner
- Center for Functional Protein Assemblies and Department of Chemistry, Technische Universität München, Garching, Germany
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Rottenaicher GJ, Absmeier RM, Meier L, Zacharias M, Buchner J. A constant domain mutation in a patient-derived antibody light chain reveals principles of AL amyloidosis. Commun Biol 2023; 6:209. [PMID: 36823438 PMCID: PMC9950467 DOI: 10.1038/s42003-023-04574-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 02/09/2023] [Indexed: 02/25/2023] Open
Abstract
Light chain (AL) amyloidosis is a debilitating disease in which mutant antibody light chains (LC), secreted by aberrant plasma cell clones, misfold and form insoluble fibrils, which can be deposited in various organs. In the majority of cases, the fibrillar deposits consist of LC variable domains (VL) containing destabilizing mutations compared to their germline counterparts. This is also true for the patient LC FOR005. However, this pathogenic LC sequence contains an additional mutation in the constant domain (CL). The mechanistic impact of CL mutations is not yet understood in the context of AL amyloidosis. Our analysis reveals that the FOR005 CL mutation influences the amyloid pathway in specific ways: (1) folding and stability of the patient CL domain are strongly impaired; (2) the mutation disrupts the LC dimer interface and weakens dimerization; (3) the CL mutation promotes proteolytic cleavage of the LC monomers resulting in an isolated, amyloidogenic VL domain while dimeric LCs are not cleaved. The enhanced proteolysis rates and the inability of full-length LCs to form amyloid fibrils even in the presence of a destabilized CL domain support a model for AL amyloidosis in which the CL domain plays a protective role and in which proteolytic cleavage precedes amyloid formation.
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Affiliation(s)
- Georg J Rottenaicher
- Center for Functional Protein Assemblies, Technical University Munich, Ernst-Otto-Fischer-Str. 8, 85748, Garching, Germany
- Department of Biosciences, TUM School of Natural Sciences, Technical University Munich, Boltzmannstr. 10, 85748, Garching, Germany
| | - Ramona M Absmeier
- Center for Functional Protein Assemblies, Technical University Munich, Ernst-Otto-Fischer-Str. 8, 85748, Garching, Germany
- Department of Biosciences, TUM School of Natural Sciences, Technical University Munich, Boltzmannstr. 10, 85748, Garching, Germany
| | - Laura Meier
- Center for Functional Protein Assemblies, Technical University Munich, Ernst-Otto-Fischer-Str. 8, 85748, Garching, Germany
- Department of Biosciences, TUM School of Natural Sciences, Technical University Munich, Boltzmannstr. 10, 85748, Garching, Germany
| | - Martin Zacharias
- Center for Functional Protein Assemblies, Technical University Munich, Ernst-Otto-Fischer-Str. 8, 85748, Garching, Germany
- Department of Biosciences, TUM School of Natural Sciences, Technical University Munich, Boltzmannstr. 10, 85748, Garching, Germany
| | - Johannes Buchner
- Center for Functional Protein Assemblies, Technical University Munich, Ernst-Otto-Fischer-Str. 8, 85748, Garching, Germany.
- Department of Biosciences, TUM School of Natural Sciences, Technical University Munich, Boltzmannstr. 10, 85748, Garching, Germany.
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