1
|
Lepley LK, Stoneback L, Macpherson PC, Butterfield TA. Eccentric Exercise as a Potent Prescription for Muscle Weakness After Joint Injury. Exerc Sport Sci Rev 2023; 51:109-116. [PMID: 37093645 PMCID: PMC10330137 DOI: 10.1249/jes.0000000000000319] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Lengthening contractions (i.e., eccentric contractions) are capable of uniquely triggering the nervous system and signaling pathways to promote tissue health/growth. This mode of exercise may be particularly potent for patients suffering from muscle weakness after joint injury. Here we provide a novel framework for eccentric exercise as a safe, effective mode of exercise prescription for muscle recovery.
Collapse
Affiliation(s)
| | - Luke Stoneback
- School of Kinesiology, University of Michigan, Ann Arbor, MI, USA
| | - Peter C.D. Macpherson
- School of Kinesiology, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Timothy A. Butterfield
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, USA
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| |
Collapse
|
2
|
Bogomolovas J, Fleming JR, Franke B, Manso B, Simon B, Gasch A, Markovic M, Brunner T, Knöll R, Chen J, Labeit S, Scheffner M, Peter C, Mayans O. Titin kinase ubiquitination aligns autophagy receptors with mechanical signals in the sarcomere. EMBO Rep 2021; 22:e48018. [PMID: 34402565 PMCID: PMC8490993 DOI: 10.15252/embr.201948018] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 07/07/2021] [Accepted: 07/19/2021] [Indexed: 12/13/2022] Open
Abstract
Striated muscle undergoes remodelling in response to mechanical and physiological stress, but little is known about the integration of such varied signals in the myofibril. The interaction of the elastic kinase region from sarcomeric titin (A168-M1) with the autophagy receptors Nbr1/p62 and MuRF E3 ubiquitin ligases is well suited to link mechanosensing with the trophic response of the myofibril. To investigate the mechanisms of signal cross-talk at this titin node, we elucidated its 3D structure, analysed its response to stretch using steered molecular dynamics simulations and explored its functional relation to MuRF1 and Nbr1/p62 using cellular assays. We found that MuRF1-mediated ubiquitination of titin kinase promotes its scaffolding of Nbr1/p62 and that the process can be dynamically down-regulated by the mechanical unfolding of a linker sequence joining titin kinase with the MuRF1 receptor site in titin. We propose that titin ubiquitination is sensitive to the mechanical state of the sarcomere, the regulation of sarcomere targeting by Nbr1/p62 being a functional outcome. We conclude that MuRF1/Titin Kinase/Nbr1/p62 constitutes a distinct assembly that predictably promotes sarcomere breakdown in inactive muscle.
Collapse
Affiliation(s)
- Julius Bogomolovas
- Department of MedicineSchool of MedicineUniversity of CaliforniaSan Diego, La JollaCAUSA
- Department of Cognitive and Clinical NeuroscienceCentral Institute of Mental HealthMedical Faculty MannheimHeidelberg UniversityMannheimGermany
- Department of Integrative PathophysiologyMedical Faculty MannheimUniversity of HeidelbergMannheimGermany
| | | | - Barbara Franke
- Department of BiologyUniversity of KonstanzKonstanzGermany
| | - Bruno Manso
- Department of BiologyUniversity of KonstanzKonstanzGermany
| | - Bernd Simon
- Structural and Computational Biology UnitEMBLHeidelbergGermany
| | - Alexander Gasch
- Department of Integrative PathophysiologyMedical Faculty MannheimUniversity of HeidelbergMannheimGermany
| | | | - Thomas Brunner
- Department of BiologyUniversity of KonstanzKonstanzGermany
| | - Ralph Knöll
- Integrated Cardio Metabolic Centre (ICMC)Heart and Vascular ThemeUniversity Hospital, MedHKarolinska InstitutetHuddingeSweden
- Bioscience, CardiovascularRenal & MetabolismBioPharmaceuticalsR&D, AstraZenecaGothenburgSweden
| | - Ju Chen
- Department of MedicineSchool of MedicineUniversity of CaliforniaSan Diego, La JollaCAUSA
| | - Siegfried Labeit
- Department of Integrative PathophysiologyMedical Faculty MannheimUniversity of HeidelbergMannheimGermany
| | | | - Christine Peter
- Department of ChemistryUniversity of KonstanzKonstanzGermany
| | - Olga Mayans
- Department of BiologyUniversity of KonstanzKonstanzGermany
| |
Collapse
|
3
|
Rodriguez K, Garcia SA, Spino C, Lepley LK, Pang Y, Wojtys E, Bedi A, Angelini M, Ruffino B, Bolley T, Block C, Kellum J, Swartout A, Palmieri-Smith RM. Michigan Initiative for Anterior Cruciate Ligament Rehabilitation (MiACLR): A Protocol for a Randomized Clinical Trial. Phys Ther 2020; 100:2154-2164. [PMID: 32939539 PMCID: PMC7720639 DOI: 10.1093/ptj/pzaa169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/18/2020] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Restoring quadriceps muscle strength following anterior cruciate ligament reconstruction (ACLR) may prevent the posttraumatic osteoarthritis that affects over 50% of knees with ACLR. However, a fundamental gap exists in our understanding of how to maximize muscle strength through rehabilitation. Neurological deficits and muscle atrophy are 2 of the leading mechanisms of muscle weakness after ACLR. High-intensity neuromuscular electrical stimulation (NMES) and eccentric exercise (ECC) have been shown to independently target these mechanisms. If delivered in succession, NMES and then ECC may be able to significantly improve strength recovery. The objectives of this study were to evaluate the ability of NMES combined with ECC to restore quadriceps strength and biomechanical symmetry and maintain cartilage health at 9 and 18 months after ACLR. METHODS This study is a randomized, double-blind, placebo-controlled, single-center clinical trial conducted at the University of Michigan. A total of 112 participants between the ages of 14 and 45 years and with an anterior cruciate ligament rupture will be included. Participants will be randomly assigned 1:1 to NMES combined with ECC or NMES placebo combined with ECC placebo. NMES or NMES placebo will be delivered 2 times per week for 8 weeks beginning 10 to 14 days postoperatively and will be directly followed by 8 weeks of ECC or ECC placebo delivered 2 times per week. The co-primary endpoints are change from baseline to 9 months and change from baseline to 18 months after ACLR in isokinetic quadriceps strength symmetry. Secondary outcome measures include isometric quadriceps strength, quadriceps activation, quadriceps muscle morphology (cross-sectional area), knee biomechanics (sagittal plane knee angles and moments), indexes of patient-reported function, and cartilage health (T1ρ and T2 relaxation time mapping on magnetic resonance imaging). IMPACT The findings from this study might identify an intervention capable of targeting the lingering quadriceps weakness after ACLR and in turn prevent deterioration in cartilage health after ACLR, thereby potentially improving function in this patient population.
Collapse
Affiliation(s)
- Kazandra Rodriguez
- School of Kinesiology, University of Michigan, Ann Arbor, Michigan; and Orthopaedic Rehabilitation and Biomechanics Laboratory, University of Michigan
| | - Steven A Garcia
- School of Kinesiology, University of Michigan; and Orthopaedic Rehabilitation and Biomechanics Laboratory, University of Michigan
| | | | - Lindsey K Lepley
- School of Kinesiology, University of Michigan; and Orthopaedic Rehabilitation and Biomechanics Laboratory, University of Michigan
| | - Yuxi Pang
- Department of Radiology, Michigan Medicine, Ann Arbor, Michigan
| | - Edward Wojtys
- Michigan Medicine; and Department of Orthopaedic Surgery, Michigan Medicine
| | - Asheesh Bedi
- Michigan Medicine; and Department of Orthopaedic Surgery, Michigan Medicine
| | - Mike Angelini
- School of Kinesiology, University of Michigan; and Orthopaedic Rehabilitation and Biomechanics Laboratory, University of Michigan
| | | | | | | | | | | | | |
Collapse
|
4
|
Sharma S, Subramani S, Popa I. Does protein unfolding play a functional role in vivo? FEBS J 2020; 288:1742-1758. [PMID: 32761965 DOI: 10.1111/febs.15508] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/09/2020] [Accepted: 08/03/2020] [Indexed: 12/21/2022]
Abstract
Unfolding and refolding of multidomain proteins under force have yet to be recognized as a major mechanism of function for proteins in vivo. In this review, we discuss the inherent properties of multidomain proteins under a force vector from a structural and functional perspective. We then characterize three main systems where multidomain proteins could play major roles through mechanical unfolding: muscular contraction, cellular mechanotransduction, and bacterial adhesion. We analyze how key multidomain proteins for each system can produce a gain-of-function from the perspective of a fine-tuned quantized response, a molecular battery, delivery of mechanical work through refolding, elasticity tuning, protection and exposure of cryptic sites, and binding-induced mechanical changes. Understanding how mechanical unfolding and refolding affect function will have important implications in designing mechano-active drugs against conditions such as muscular dystrophy, cancer, or novel antibiotics.
Collapse
Affiliation(s)
- Sabita Sharma
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Smrithika Subramani
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Ionel Popa
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| |
Collapse
|
5
|
Lepley LK, Davi SM, Hunt ER, Burland JP, White MS, McCormick GY, Butterfield TA. Morphology and Anabolic Response of Skeletal Muscles Subjected to Eccentrically or Concentrically Biased Exercise. J Athl Train 2020; 55:336-342. [PMID: 32196379 DOI: 10.4085/1062-6050-174-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
CONTEXT Long-term eccentric exercise is known to promote muscle growth better than concentric exercise, but its acute effect on muscle is not well understood because of misinterpreted modeling and in situ and in vitro stretch protocols. Knowing if the initial bout of eccentric exercise promotes muscle growth and limits damage is critical to understanding the effect of this mode of exercise. OBJECTIVE To directly evaluate the immediate effects of eccentric and concentric exercises on untrained muscle when fiber strains were physiological and exercise doses were comparable. DESIGN Controlled laboratory study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS A total of 40 skeletally mature male Long-Evans rats (age = 16 weeks, mass = 452.1 ± 35.2 g) were randomly assigned to an eccentric exercise (downhill walking, n = 16), concentric exercise (uphill walking, n = 16), or control (no exercise, n = 8) group. INTERVENTION(S) Rats were exposed to a single 15-minute bout of eccentric or concentric exercise on a motorized treadmill and then were euthanized at 6 or 24 hours postexercise. We harvested the vastus lateralis muscle bilaterally. MAIN OUTCOME MEASURE(S) The percentage increase or decrease in protein abundance in exercised animals relative to that in unexercised control animals was evaluated as elevated phosphorylated p70S6k relative to total p70S6k. Fiber damage was quantified using immunoglobulin G permeability staining. One-way analysis of variance and post hoc Tukey tests were performed. RESULTS Rats exposed to eccentric exercise and euthanized at 24 hours had higher percentage response protein synthesis rates than rats exposed to eccentric exercise and euthanized at 6 hours (P = .02) or to concentric exercise and euthanized at 6 (P = .03) or 24 (P = .03) hours. We assessed 9446 fibers for damage and found only 1 fiber was infiltrated (in the concentric exercise group euthanized at 6 hours). Furthermore, no between-groups differences in immunoglobulin G fluorescent intensity were detected (P = .94). CONCLUSIONS Incorporating eccentric exercise is a simple, universally available therapeutic intervention for promoting muscle recovery. A single 15-minute dose of eccentric exercise to a novice muscle can better exert an anabolic effect than a comparable dose of concentric exercise, with very limited evidence of fiber damage.
Collapse
Affiliation(s)
| | - Steven M Davi
- Department of Kinesiology, University of Connecticut, Storrs
| | - Emily R Hunt
- Department of Rehabilitation Sciences, University of Kentucky, Lexington.,Center for Muscle Biology, University of Kentucky, Lexington
| | - Julie P Burland
- Spaulding National Running Center, Harvard Medical School, Boston, MA
| | | | | | - Timothy A Butterfield
- Department of Rehabilitation Sciences, University of Kentucky, Lexington.,Center for Muscle Biology, University of Kentucky, Lexington
| |
Collapse
|
6
|
Yakupova EI, Vikhlyantsev IM, Lobanov MY, Galzitskaya OV, Bobylev AG. Amyloid Properties of Titin. BIOCHEMISTRY (MOSCOW) 2018. [PMID: 29523065 DOI: 10.1134/s0006297917130077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This review considers data on structural and functional features of titin, on the role of this protein in determination of mechanical properties of sarcomeres, and on specific features of regulation of the stiffness and elasticity of its molecules, amyloid aggregation of this protein in vitro, and possibilities of formation of intramolecular amyloid structure in vivo. Molecular mechanisms are described of protection of titin against aggregation in muscle cells. Based on the data analysis, it is supposed that titin and the formed by it elastic filaments have features of amyloid.
Collapse
Affiliation(s)
- E I Yakupova
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
| | | | | | | | | |
Collapse
|
7
|
Abstract
Context: Neuromuscular alterations are a major causal factor of primary and secondary injuries. Though injury prevention programs have experienced some success, rates of injuries have not declined, and after injury, individuals often return to activity with functionality below clinical recommendations. Considering alternative therapies to the conventional concentric exercise approach, such as one that can target neuromuscular injury risk and postinjury alterations, may provide for more effective injury prevention and rehabilitation protocols. Evidence Acquisition: Peer-reviewed sources available on the Web of Science and MEDLINE databases from 2000 through 2016 were gathered using searches associated with the keywords eccentric exercise, injury prevention, and neuromuscular control. Hypothesis: Eccentric exercise will reduce injury risk by targeting specific neural and morphologic alterations that precipitate neuromuscular dysfunction. Study Design: Clinical review. Level of Evidence: Level 4. Results: Neuromuscular control is influenced by alterations in muscle morphology and neural activity. Eccentric exercise beneficially modifies several underlying factors of muscle morphology (fiber typing, cross-sectional area, working range, and pennation angle), and emerging evidence indicates that eccentric exercise is also beneficial to peripheral and central neural activity (alpha motorneuron recruitment/firing, sarcolemma activity, corticospinal excitability, and brain activation). Conclusion: There is mounting evidence that eccentric exercise is not only a therapeutic intervention influencing muscle morphology but also targets unique alterations in neuromuscular control, influencing injury risk.
Collapse
Affiliation(s)
- Lindsey K Lepley
- Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| | - Adam S Lepley
- Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| | - James A Onate
- School of Health and Rehabilitative Sciences, College of Medicine, The Ohio State University, Columbus, Ohio
| | - Dustin R Grooms
- Ohio Musculoskeletal & Neurological Institute, Ohio University, Athens, Ohio.,Division of Athletic Training, School of Applied Health Sciences and Wellness, College of Health Sciences and Professions, Ohio University, Athens, Ohio
| |
Collapse
|
8
|
Anosov AA, Kuprijanova MS, Nemchenko OY, Norik VP, Sergeenko EV, Smirnova EY. States of lipid pores in bilayer lipid membranes at a phase transition in a LiCl solution with addition of molecules of polyethylene glycol. Biophysics (Nagoya-shi) 2015. [DOI: 10.1134/s0006350915010029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
9
|
Iliafar S, Mittal J, Vezenov D, Jagota A. Interaction of single-stranded DNA with curved carbon nanotube is much stronger than with flat graphite. J Am Chem Soc 2014; 136:12947-57. [PMID: 25162693 DOI: 10.1021/ja5055498] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We used single molecule force spectroscopy to measure the force required to remove single-stranded DNA (ssDNA) homopolymers from single-walled carbon nanotubes (SWCNTs) deposited on methyl-terminated self-assembled monolayers (SAMs). The peeling forces obtained from these experiments are bimodal in distribution. The cluster of low forces corresponds to peeling from the SAM surface, while the cluster of high forces corresponds to peeling from the SWCNTs. Using a simple equilibrium model of the single molecule peeling process, we calculated the free energy of binding per nucleotide. We found that the free energy of ssDNA binding to hydrophobic SAMs decreases as poly(A) > poly(G) ≈ poly(T) > poly(C) (16.9 ± 0.1; 9.7 ± 0.1; 9.5 ± 0.1; 8.7 ± 0.1 kBT, per nucleotide). The free energy of ssDNA binding to SWCNT adsorbed on this SAM also decreases in the same order poly(A) > poly(G) > poly(T) > poly(C), but its magnitude is significantly greater than that of DNA-SAM binding energy (38.1 ± 0.2; 33.9 ± 0.1; 23.3 ± 0.1; 17.1 ± 0.1 kBT, per nucleotide). An unexpected finding is that binding strength of ssDNA to the curved SWCNTs is much greater than to flat graphite, which also has a different ranking (poly(T) > poly(A) > poly(G) ≥ poly(C); 11.3 ± 0.8, 9.9 ± 0.5, 8.3 ± 0.2, and 7.5 ± 0.8 kBT, respectively, per nucleotide). Replica-exchange molecular dynamics simulations show that ssDNA binds preferentially to the curved SWCNT surface, leading us to conclude that the differences in ssDNA binding between graphite and nanotubes arise from the spontaneous curvature of ssDNA.
Collapse
Affiliation(s)
- Sara Iliafar
- Department of Chemical and Biomolecular Engineering and ‡Bioengineering Program, Lehigh University , Bethlehem, Pennsylvania 18015, United States
| | | | | | | |
Collapse
|
10
|
Mechanistic and functional diversity in the mechanosensory kinases of the titin-like family. Biochem Soc Trans 2013; 41:1066-71. [DOI: 10.1042/bst20130085] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The giant cytoskeletal kinases of the titin-like family are emerging as key mediators of stretch-sensing in muscle. It is thought that their elastic conformational deformation during muscle function regulates both their catalysis and the recruitment of regulatory proteins to signalosomes that assemble in their vicinity. In the present article, we discuss the speciation of mechanosensory mechanisms in titin-like kinases, their scaffolding properties and the kinase/pseudokinase domain variations that define a rich functional diversity across the family.
Collapse
|
11
|
Vikhlyantsev IM, Podlubnaya ZA. New titin (connectin) isoforms and their functional role in striated muscles of mammals: facts and suppositions. BIOCHEMISTRY (MOSCOW) 2013; 77:1515-35. [PMID: 23379526 DOI: 10.1134/s0006297912130093] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
This review summarizes results of our studies on titin isoform composition in vertebrate striated muscles under normal conditions, during hibernation, real and simulated microgravity, and under pathological conditions (stiff-person syndrome, post-apoplectic spasticity, dilated cardiomyopathy, cardiac hypertrophy). Experimental evidence for the existence in mammalian striated muscles of higher molecular weight isoforms of titin (NT-isoforms) in addition to the known N2A-, N2BA-, and N2B-titin isoforms was obtained. Comparative studies of changes in titin isoform composition and structure-functional properties of human and animal striated muscles during adaptive and pathological processes led to a conclusion about the key role of NT-isoforms of titin in maintenance of sarcomere structure and contractile function of these muscles.
Collapse
Affiliation(s)
- I M Vikhlyantsev
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
| | | |
Collapse
|
12
|
Temmerman K, Simon B, Wilmanns M. Structural and functional diversity in the activity and regulation of DAPK-related protein kinases. FEBS J 2013; 280:5533-50. [PMID: 23745726 DOI: 10.1111/febs.12384] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 06/06/2013] [Accepted: 06/07/2013] [Indexed: 11/30/2022]
Abstract
Within the large group of calcium/calmodulin-dependent protein kinases (CAMKs) of the human kinome, there is a distinct branch of highly related kinases that includes three families: death-associated protein-related kinases, myosin light-chain-related kinases and triple functional domain protein-related kinases. In this review, we refer to these collectively as DMT kinases. There are several functional features that span the three families, such as a broad involvement in apoptotic processes, cytoskeletal association and cellular plasticity. Other CAMKs contain a highly conserved HRD motif, which is a prerequisite for kinase regulation through activation-loop phosphorylation, but in all 16 members of the DMT branch, this is replaced by an HF/LD motif. This DMT kinase signature motif substitutes phosphorylation-dependent active-site interactions with a local hydrophobic core that maintains an active kinase conformation. Only about half of the DMT kinases have an additional autoregulatory domain, C-terminal to the kinase domain that binds calcium/calmodulin in order to regulate kinase activity. Protein substrates have been identified for some of the DMT kinases, but little is known about the mechanism of recognition. Substrate conformation could be an equally important parameter in substrate recognition as specific preferences in sequence position. Taking the data together, this kinase branch encapsulates a treasure trove of features that renders it distinct from many other protein kinases and calls for future research activities in this field.
Collapse
|
13
|
Zheng P, Takayama SIJ, Mauk AG, Li H. Single Molecule Force Spectroscopy Reveals That Iron Is Released from the Active Site of Rubredoxin by a Stochastic Mechanism. J Am Chem Soc 2013; 135:7992-8000. [DOI: 10.1021/ja402150q] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Peng Zheng
- Department of Chemistry, University of British Columbia, Vancouver, British
Columbia V6T 1Z1, Canada
| | - Shin-ichi J. Takayama
- Department of Biochemistry and
Molecular Biology and the Center for Blood Research, University of British Columbia, Vancouver, British
Columbia V6T 1Z3, Canada
| | - A. Grant Mauk
- Department of Biochemistry and
Molecular Biology and the Center for Blood Research, University of British Columbia, Vancouver, British
Columbia V6T 1Z3, Canada
| | - Hongbin Li
- Department of Chemistry, University of British Columbia, Vancouver, British
Columbia V6T 1Z1, Canada
| |
Collapse
|
14
|
Bujalowski PJ, Oberhauser AF. Tracking unfolding and refolding reactions of single proteins using atomic force microscopy methods. Methods 2013; 60:151-60. [PMID: 23523554 DOI: 10.1016/j.ymeth.2013.03.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 03/07/2013] [Accepted: 03/11/2013] [Indexed: 11/26/2022] Open
Abstract
During the last two decades single-molecule manipulation techniques such as atomic force microscopy (AFM) has risen to prominence through their unique capacity to provide fundamental information on the structure and function of biomolecules. Here we describe the use of single-molecule AFM to track protein unfolding and refolding pathways, enzymatic catalysis and the effects of osmolytes and chaperones on protein stability and folding. We will outline the principles of operation for two different AFM pulling techniques: length clamp and force-clamp and discuss prominent applications. We provide protocols for the construction of polyproteins which are amenable for AFM experiments, the preparation of different coverslips, choice and calibration of AFM cantilevers. We also discuss the selection criteria for AFM recordings, the calibration of AFM cantilevers, protein sample preparations and analysis of the obtained data.
Collapse
Affiliation(s)
- Paul J Bujalowski
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, TX 77555, USA
| | | |
Collapse
|
15
|
Mitrea DM, Kriwacki RW. Regulated unfolding of proteins in signaling. FEBS Lett 2013; 587:1081-8. [PMID: 23454209 DOI: 10.1016/j.febslet.2013.02.024] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 02/12/2013] [Accepted: 02/13/2013] [Indexed: 11/27/2022]
Abstract
The transduction of biological signals often involves structural rearrangements of proteins in response to input signals, which leads to functional outputs. This review discusses the role of regulated partial and complete protein unfolding as a mechanism of controlling protein function and the prevalence of this regulatory mechanism in signal transduction pathways. The principles of regulated unfolding, the stimuli that trigger unfolding, and the coupling of unfolding with other well characterized regulatory mechanism are discussed.
Collapse
Affiliation(s)
- Diana M Mitrea
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | | |
Collapse
|
16
|
Identification of an N-terminal inhibitory extension as the primary mechanosensory regulator of twitchin kinase. Proc Natl Acad Sci U S A 2012; 109:13608-13. [PMID: 22869697 DOI: 10.1073/pnas.1200697109] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Titin-like kinases are an important class of cytoskeletal kinases that intervene in the response of muscle to mechanical stimulation, being central to myofibril homeostasis and development. These kinases exist in autoinhibited states and, allegedly, become activated during muscle activity by the elastic unfolding of a C-terminal regulatory segment (CRD). However, this mechano-activation model remains controversial. Here we explore the structural, catalytic, and tensile properties of the multidomain kinase region of Caenorhabditis elegans twitchin (Fn(31)-Nlinker-kinase-CRD-Ig(26)) using X-ray crystallography, small angle X-ray scattering, molecular dynamics simulations, and catalytic assays. This work uncovers the existence of an inhibitory segment that flanks the kinase N-terminally (N-linker) and that acts synergistically with the canonical CRD tail to silence catalysis. The N-linker region has high mechanical lability and acts as the primary stretch-sensor in twitchin kinase, while the CRD is poorly responsive to pulling forces. This poor response suggests that the CRD is not a generic mechanosensor in this kinase family. Instead, the CRD is shown here to be permissive to catalysis and might protect the kinase active site against mechanical damage. Thus, we put forward a regulatory model where kinase inhibition results from the combined action of both N- and C-terminal tails, but only the N-terminal extension undergoes mechanical removal, thereby affording partial activation. Further, we compare invertebrate and vertebrate titin-like kinases and identify variations in the regulatory segments that suggest a mechanical speciation of these kinase classes.
Collapse
|
17
|
Affiliation(s)
- Elias M. Puchner
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California 94158;
| | - Hermann E. Gaub
- Center for Nanoscience and Department of Physics, University of Munich, 80799 Munich, Germany;
| |
Collapse
|
18
|
Kho AL, Perera S, Alexandrovich A, Gautel M. The sarcomeric cytoskeleton as a target for pharmacological intervention. Curr Opin Pharmacol 2012; 12:347-54. [DOI: 10.1016/j.coph.2012.03.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 03/14/2012] [Accepted: 03/16/2012] [Indexed: 01/10/2023]
|