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Extreme escalation of heat failure rates in ectotherms with global warming. Nature 2022; 611:93-98. [DOI: 10.1038/s41586-022-05334-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 09/09/2022] [Indexed: 11/08/2022]
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2
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Yadav S, Kunwar A. Temperature-Dependent Activity of Motor Proteins: Energetics and Their Implications for Collective Behavior. Front Cell Dev Biol 2021; 9:610899. [PMID: 33732692 PMCID: PMC7959718 DOI: 10.3389/fcell.2021.610899] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 01/11/2021] [Indexed: 12/27/2022] Open
Abstract
Molecular motor proteins are an extremely important component of the cellular transport system that harness chemical energy derived from ATP hydrolysis to carry out directed mechanical motion inside the cells. Transport properties of these motors such as processivity, velocity, and their load dependence have been well established through single-molecule experiments. Temperature dependent biophysical properties of molecular motors are now being probed using single-molecule experiments. Additionally, the temperature dependent biochemical properties of motors (ATPase activity) are probed to understand the underlying mechanisms and their possible implications on the enzymatic activity of motor proteins. These experiments in turn have revealed their activation energies and how they compare with the thermal energy available from the surrounding medium. In this review, we summarize such temperature dependent biophysical and biochemical properties of linear and rotary motor proteins and their implications for collective function during intracellular transport and cellular movement, respectively.
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Affiliation(s)
- Saumya Yadav
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Ambarish Kunwar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
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3
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Collar DC, Thompson JS, Ralston TC, Hobbs TJ. Fast-start escape performance across temperature and salinity gradients in mummichog Fundulus heteroclitus. JOURNAL OF FISH BIOLOGY 2020; 96:755-767. [PMID: 32010969 DOI: 10.1111/jfb.14273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 01/29/2020] [Indexed: 06/10/2023]
Abstract
Fast-start predator-escape performance of mummichogs Fundulus heteroclitus was tested across field-informed variation in temperature (24, 30 and 36°C) and salinity (2, 12 and 32 ppt). Performance was similar across temperatures and salinities when fish were allowed to acclimate to these conditions. However, when mummichogs experienced acute temperature changes, performance exhibited thermal dependence in two contrasting ways. Fast-start turning rates and linear speeds varied directly with the temperature at which the manoeuvre was executed, but these aspects of performance varied inversely with acclimation temperature, with cool-acclimated fish exhibiting faster starts across test temperatures. Temperature effects were consistent across salinities. These results suggest that while mummichogs increase performance with acute temperature increases, long-term rises in sea temperature may cause these fish to become more susceptible to predation during abrupt cooling events, such as when storm events flood shallow water estuaries with cool rainwater.
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Affiliation(s)
- David C Collar
- Department of Organismal and Environmental Biology, Christopher Newport University, Newport News, Virginia, USA
| | - Jessica S Thompson
- Department of Organismal and Environmental Biology, Christopher Newport University, Newport News, Virginia, USA
| | - Tyler C Ralston
- Department of Organismal and Environmental Biology, Christopher Newport University, Newport News, Virginia, USA
| | - Trevor J Hobbs
- Department of Organismal and Environmental Biology, Christopher Newport University, Newport News, Virginia, USA
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4
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Lefevre S. Effects of high CO2 on oxygen consumption rates, aerobic scope and swimming performance. FISH PHYSIOLOGY 2019. [DOI: 10.1016/bs.fp.2019.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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Gilda JE, Xu Q, Martinez ME, Nguyen ST, Chase PB, Gomes AV. The functional significance of the last 5 residues of the C-terminus of cardiac troponin I. Arch Biochem Biophys 2016; 601:88-96. [PMID: 26919894 PMCID: PMC4899223 DOI: 10.1016/j.abb.2016.02.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 02/06/2016] [Accepted: 02/22/2016] [Indexed: 11/15/2022]
Abstract
The C-terminal region of cardiac troponin I (cTnI) is known to be important in cardiac function, as removal of the last 17 C-terminal residues of human cTnI has been associated with myocardial stunning. To investigate the C-terminal region of cTnI, three C-terminal deletion mutations in human cTnI were generated: Δ1 (deletion of residue 210), Δ3 (deletion of residues 208-210), and Δ5 (deletion of residues 206-210). Mammalian two-hybrid studies showed that the interactions between cTnI mutants and cardiac troponin C (cTnC) or cardiac troponin T (cTnT) were impaired in Δ3 and Δ5 mutants when compared to wild-type cTnI. Troponin complexes containing 2-[4'-(iodoacetamido) anilino] naphthalene-6-sulfonic acid (IAANS) labeled cTnC showed that the troponin complex containing cTnI Δ5 had a small increase in Ca(2+) affinity (P < 0.05); while the cTnI Δ1- and Δ3 troponin complexes showed no difference in Ca(2+) affinity when compared to wild-type troponin. In vitro motility assays showed that all truncation mutants had increased Ca(2+) dependent motility relative to wild-type cTnI. These results suggest that the last 5 C-terminal residues of cTnI influence the binding of cTnI with cTnC and cTnT and affect the Ca(2+) dependence of filament sliding, and demonstrate the importance of this region of cTnI.
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Affiliation(s)
- Jennifer E Gilda
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, 95616, USA
| | - Qian Xu
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, 95616, USA
| | - Margaret E Martinez
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Susan T Nguyen
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, 95616, USA
| | - P Bryant Chase
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Aldrin V Gomes
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, 95616, USA.
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Brunet NM, Chase PB, Mihajlović G, Schoffstall B. Ca(2+)-regulatory function of the inhibitory peptide region of cardiac troponin I is aided by the C-terminus of cardiac troponin T: Effects of familial hypertrophic cardiomyopathy mutations cTnI R145G and cTnT R278C, alone and in combination, on filament sliding. Arch Biochem Biophys 2014; 552-553:11-20. [PMID: 24418317 PMCID: PMC4043889 DOI: 10.1016/j.abb.2013.12.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 12/10/2013] [Accepted: 12/28/2013] [Indexed: 01/10/2023]
Abstract
Investigations of cardiomyopathy mutations in Ca(2+) regulatory proteins troponin and tropomyosin provide crucial information about cardiac disease mechanisms, and also provide insights into functional domains in the affected polypeptides. Hypertrophic cardiomyopathy-associated mutations TnI R145G, located within the inhibitory peptide (Ip) of human cardiac troponin I (hcTnI), and TnT R278C, located immediately C-terminal to the IT arm in human cardiac troponin T (hcTnT), share some remarkable features: structurally, biochemically, and pathologically. Using bioinformatics, we find compelling evidence that TnI and TnT, and more specifically the affected regions of hcTnI and hcTnT, may be related not just structurally but also evolutionarily. To test for functional interactions of these mutations on Ca(2+)-regulation, we generated and characterized Tn complexes containing either mutation alone, or both mutations simultaneously. The most important results from in vitro motility assays (varying [Ca(2+)], temperature or HMM density) show that the TnT mutant "rescued" some deleterious effects of the TnI mutant at high Ca(2+), but exacerbated the loss of function, i.e., switching off the actomyosin interaction, at low Ca(2+). Taken together, our experimental results suggest that the C-terminus of cTnT aids Ca(2+)-regulatory function of cTnI Ip within the troponin complex.
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Affiliation(s)
- Nicolas M Brunet
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
| | - P Bryant Chase
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA; Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA.
| | - Goran Mihajlović
- Department of Physics, Florida State University, Tallahassee, FL 32306, USA
| | - Brenda Schoffstall
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
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Whittington AC, Nienow TE, Whittington CL, Fort TJ, Grove TJ. Functional and structural characterization of a eurytolerant calsequestrin from the intertidal teleost Fundulus heteroclitus. PLoS One 2012; 7:e50801. [PMID: 23226387 PMCID: PMC3511267 DOI: 10.1371/journal.pone.0050801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 10/25/2012] [Indexed: 02/07/2023] Open
Abstract
Calsequestrins (CSQ) are high capacity, medium affinity, calcium-binding proteins present in the sarcoplasmic reticulum (SR) of cardiac and skeletal muscles. CSQ sequesters Ca2+ during muscle relaxation and increases the Ca2+-storage capacity of the SR. Mammalian CSQ has been well studied as a model of human disease, but little is known about the environmental adaptation of CSQ isoforms from poikilothermic organisms. The mummichog, Fundulus heteroclitus, is an intertidal fish that experiences significant daily and seasonal environmental fluctuations and is an interesting study system for investigations of adaptation at the protein level. We determined the full-length coding sequence of a CSQ isoform from skeletal muscle of F. heteroclitus (FCSQ) and characterized the function and structure of this CSQ. The dissociation constant (Kd) of FCSQ is relatively insensitive to changes in temperature and pH, thus indicating that FCSQ is a eurytolerant protein. We identified and characterized a highly conserved salt bridge network in FCSQ that stabilizes the formation of front-to-front dimers, a process critical to CSQ function. The functional profile of FCSQ correlates with the natural history of F. heteroclitus suggesting that the eurytolerant function of FCSQ may be adaptive.
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Affiliation(s)
- A. Carl Whittington
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, United States of America
| | - Tatyana E. Nienow
- Department of Biology, Valdosta State University, Valdosta, Georgia, United States of America
| | - Christi L. Whittington
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Timothy J. Fort
- Department of Biology, Valdosta State University, Valdosta, Georgia, United States of America
| | - Theresa J. Grove
- Department of Biology, Valdosta State University, Valdosta, Georgia, United States of America
- * E-mail:
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Elangovan R, Capitanio M, Melli L, Pavone FS, Lombardi V, Piazzesi G. An integrated in vitro and in situ study of kinetics of myosin II from frog skeletal muscle. J Physiol 2012; 590:1227-42. [PMID: 22199170 PMCID: PMC3381827 DOI: 10.1113/jphysiol.2011.222984] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 12/23/2011] [Indexed: 11/08/2022] Open
Abstract
A new efficient protocol for extraction and conservation of myosin II from frog skeletal muscle made it possible to preserve the myosin functionality for a week and apply single molecule techniques to the molecular motor that has been best characterized for its mechanical, structural and energetic parameters in situ.With the in vitro motility assay, we estimated the sliding velocity of actin on frog myosin II (VF) and its modulation by pH, myosin density, temperature (range 4-30◦C) and substrate concentration. VF was 8.88 ± 0.26 μms⁻¹ at 30.6◦C and decreased to 1.60 ± 0.09 μms⁻¹ at 4.5◦C. The in vitro mechanical and kinetic parameters were integrated with the in situ parameters of frog muscle myosin working in arrays in each half-sarcomere. By comparing VF with the shortening velocities determined in intact frog muscle fibres under different loads and their dependence on temperature, we found that VF is 40-50% less than the fibre unloaded shortening velocity (V0) at the same temperature and we determined the load that explains the reduced value of VF. With this integrated approach we could define fundamental kinetic steps of the acto-myosin ATPase cycle in situ and their relation with mechanical steps. In particular we found that at 5◦C the rate of ADP release calculated using the step size estimated from in situ experiments accounts for the rate of detachment of motors during steady shortening under low loads.
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Affiliation(s)
- R Elangovan
- Laboratory of Physiology, DBE, Università di FirenzeItaly
| | - M Capitanio
- European Laboratory for Non-linear SpectroscopyFirenze, Italy
| | - L Melli
- Laboratory of Physiology, DBE, Università di FirenzeItaly
| | - F S Pavone
- European Laboratory for Non-linear SpectroscopyFirenze, Italy
| | - V Lombardi
- Laboratory of Physiology, DBE, Università di FirenzeItaly
| | - G Piazzesi
- Laboratory of Physiology, DBE, Università di FirenzeItaly
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Micromechanical thermal assays of Ca2+-regulated thin-filament function and modulation by hypertrophic cardiomyopathy mutants of human cardiac troponin. J Biomed Biotechnol 2012; 2012:657523. [PMID: 22500102 PMCID: PMC3303698 DOI: 10.1155/2012/657523] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 11/02/2011] [Indexed: 11/17/2022] Open
Abstract
Microfabricated thermoelectric controllers can be employed to investigate mechanisms underlying myosin-driven sliding of Ca(2+)-regulated actin and disease-associated mutations in myofilament proteins. Specifically, we examined actin filament sliding-with or without human cardiac troponin (Tn) and α-tropomyosin (Tm)-propelled by rabbit skeletal heavy meromyosin, when temperature was varied continuously over a wide range (~20-63°C). At the upper end of this temperature range, reversible dysregulation of thin filaments occurred at pCa 9 and 5; actomyosin function was unaffected. Tn-Tm enhanced sliding speed at pCa 5 and increased a transition temperature (T(t)) between a high activation energy (E(a)) but low temperature regime and a low E(a) but high temperature regime. This was modulated by factors that alter cross-bridge number and kinetics. Three familial hypertrophic cardiomyopathy (FHC) mutations, cTnI R145G, cTnI K206Q, and cTnT R278C, cause dysregulation at temperatures ~5-8°C lower; the latter two increased speed at pCa 5 at all temperatures.
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Warren B, Lukashkin AN, Russell IJ. The dynein-tubulin motor powers active oscillations and amplification in the hearing organ of the mosquito. Proc Biol Sci 2010; 277:1761-9. [PMID: 20129974 DOI: 10.1098/rspb.2009.2355] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The design principles and specific proteins of the dynein-tubulin motor, which powers the flagella and cilia of eukaryotes, have been conserved throughout the evolution of life from algae to humans. Cilia and flagella can support both motile and sensory functions independently, or sometimes in parallel to each other. In this paper we show that this dual sensory-motile role of eukaryotic cilia is preserved in the most sensitive of all invertebrate hearing organs, the Johnston's organ of the mosquito. The Johnston's organ displays spontaneous oscillations, which have been identified as being a characteristic of amplification in the ears of mosquitoes and Drosophila. In the auditory organs of Drosophila and vertebrates, the molecular basis of amplification has been attributed to the gating and adaptation of the mechanoelectrical transducer channels themselves. On the basis of their temperature-dependence and sensitivity to colchicine, we attribute the molecular basis of spontaneous oscillations by the Johnston's organ of the mosquito Culex quinquefasciatus, to the dynein-tubulin motor of the ciliated sensillae. If, as has been claimed for insect and vertebrate hearing organs, spontaneous oscillations epitomize amplification, then in the mosquito ear, this process is independent of mechanotransduction.
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Affiliation(s)
- Ben Warren
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
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