1
|
Squarci C, Campbell KS. Myosins may know when to hold and when to fold. Biophys J 2024; 123:525-526. [PMID: 38297835 PMCID: PMC10938075 DOI: 10.1016/j.bpj.2024.01.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/12/2024] [Accepted: 01/26/2024] [Indexed: 02/02/2024] Open
Affiliation(s)
- Caterina Squarci
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, Kentucky
| | - Kenneth S Campbell
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, Kentucky.
| |
Collapse
|
2
|
Marcello M, Cetrangolo V, Morotti I, Squarci C, Caremani M, Reconditi M, Savarese M, Bianco P, Piazzesi G, Lombardi V, Udd B, Conte I, Nigro V, Linari M. Sarcomere level mechanics of the fast skeletal muscle of the medaka fish larva. Am J Physiol Cell Physiol 2024; 326:C632-C644. [PMID: 38145303 DOI: 10.1152/ajpcell.00530.2023] [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: 10/12/2023] [Revised: 12/17/2023] [Accepted: 12/18/2023] [Indexed: 12/26/2023]
Abstract
The medaka fish (Oryzias latipes) is a vertebrate model used in developmental biology and genetics. Here we explore its suitability as a model for investigating the molecular mechanisms of human myopathies caused by mutations in sarcomeric proteins. To this end, the relevant mechanical parameters of the intact skeletal muscle of wild-type medaka are determined using the transparent tail at larval stage 40. Tails were mounted at sarcomere length of 2.1 μm in a thermoregulated trough containing physiological solution. Tetanic contractions were elicited at physiological temperature (10°C-30°C) by electrical stimulation, and sarcomere length changes were recorded with nanometer-microsecond resolution during both isometric and isotonic contractions with a striation follower. The force output has been normalized for the actual fraction of the cross section of the tail occupied by the myofilament lattice, as established with transmission electron microscopy (TEM), and then for the actual density of myofilaments, as established with X-ray diffraction. Under these conditions, the mechanical performance of the contracting muscle of the wild-type larva can be defined at the level of the half-thick filament, where ∼300 myosin motors work in parallel as a collective motor, allowing a detailed comparison with the established performance of the skeletal muscle of different vertebrates. The results of this study point out that the medaka fish larva is a suitable model for the investigation of the genotype/phenotype correlations and therapeutic possibilities in skeletal muscle diseases caused by mutations in sarcomeric proteins.NEW & NOTEWORTHY The suitability of the medaka fish as a model for investigating the molecular mechanisms of human myopathies caused by mutations of sarcomeric proteins is tested by combining structural analysis and sarcomere-level mechanics of the skeletal muscle of the tail of medaka larva. The mechanical performance of the medaka muscle, scaled at the level of the myosin-containing thick filament, together with its reduced genome duplication makes this model unique for investigations of the genotype/phenotype correlations in human myopathies.
Collapse
Affiliation(s)
| | - Viviana Cetrangolo
- PhysioLab, University of Florence, Florence, Italy
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | | | | | | | | | - Marco Savarese
- Folkhälsan Research Center, Helsinki University, Helsinki, Finland
| | | | | | | | - Bjarne Udd
- Folkhälsan Research Center, Helsinki University, Helsinki, Finland
| | - Ivan Conte
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
- Department of Biology, University of Naples "Federico II", Naples, Italy
| | - Vincenzo Nigro
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
- Department of Precision Medicine, University of Campania, Naples, Italy
| | - Marco Linari
- PhysioLab, University of Florence, Florence, Italy
| |
Collapse
|
3
|
Caremani M, Marcello M, Morotti I, Pertici I, Squarci C, Reconditi M, Bianco P, Piazzesi G, Lombardi V, Linari M. The force of the myosin motor sets cooperativity in thin filament activation of skeletal muscles. Commun Biol 2022; 5:1266. [DOI: 10.1038/s42003-022-04184-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 10/28/2022] [Indexed: 11/19/2022] Open
Abstract
AbstractContraction of striated muscle is regulated by a dual mechanism involving both thin, actin-containing filament and thick, myosin-containing filament. Thin filament is activated by Ca2+ binding to troponin, leading to tropomyosin displacement that exposes actin sites for interaction with myosin motors, extending from the neighbouring stress-activated thick filaments. Motor attachment to actin contributes to spreading activation along the thin filament, through a cooperative mechanism, still unclear, that determines the slope of the sigmoidal relation between isometric force and pCa (−log[Ca2+]), estimated by Hill coefficient nH. We use sarcomere-level mechanics in demembranated fibres of rabbit skeletal muscle activated by Ca2+ at different temperatures (12–35 °C) to show that nH depends on the motor force at constant number of attached motors. The definition of the role of motor force provides fundamental constraints for modelling the dynamics of thin filament activation and defining the action of small molecules as possible therapeutic tools.
Collapse
|
4
|
Squarci C, Bianco P, Reconditi M, Pertici I, Caremani M, Narayanan T, Horvath AI, Malnasi-Csizmadia A, Linari M, Lombardi V, Piazzesi G. Passive and active mechanical properties of titin studied in intact frog muscle fibers upon inhibition of myosin motors by para-nitro-blebbistatin. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.2713] [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: 11/02/2022] Open
|
5
|
Pertici I, Bongini L, Melli L, Bianchi G, Salvi L, Falorsi G, Squarci C, Bozó T, Cojoc D, Kellermayer MSZ, Lombardi V, Bianco P. A myosin II nanomachine mimicking the striated muscle. Nat Commun 2018; 9:3532. [PMID: 30166542 PMCID: PMC6117265 DOI: 10.1038/s41467-018-06073-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 08/02/2018] [Indexed: 11/08/2022] Open
Abstract
The contraction of striated muscle (skeletal and cardiac muscle) is generated by ATP-dependent interactions between the molecular motor myosin II and the actin filament. The myosin motors are mechanically coupled along the thick filament in a geometry not achievable by single-molecule experiments. Here we show that a synthetic one-dimensional nanomachine, comprising fewer than ten myosin II dimers purified from rabbit psoas, performs isometric and isotonic contractions at 2 mM ATP, delivering a maximum power of 5 aW. The results are explained with a kinetic model fitted to the performance of mammalian skeletal muscle, showing that the condition for the motor coordination that maximises the efficiency in striated muscle is a minimum of 32 myosin heads sharing a common mechanical ground. The nanomachine offers a powerful tool for investigating muscle contractile-protein physiology, pathology and pharmacology without the potentially disturbing effects of the cytoskeletal-and regulatory-protein environment.
Collapse
Affiliation(s)
- Irene Pertici
- PhysioLab, University of Florence, Florence, 50019, Italy
| | | | - Luca Melli
- PhysioLab, University of Florence, Florence, 50019, Italy
- F. Hoffmann-La Roche Ltd, Basel, 4053, Switzerland
| | - Giulio Bianchi
- PhysioLab, University of Florence, Florence, 50019, Italy
| | - Luca Salvi
- PhysioLab, University of Florence, Florence, 50019, Italy
- Department of Biochemistry, University of Munich, Munich, 81377, Germany
| | - Giulia Falorsi
- PhysioLab, University of Florence, Florence, 50019, Italy
| | | | - Tamás Bozó
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, H-1094, Hungary
| | | | - Miklós S Z Kellermayer
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, H-1094, Hungary
| | | | | |
Collapse
|