Sarcomeres, the basic contractile units of striated muscle cells, contain arrays of thin (actin) and thick (myosin) filaments that slide past each other during contraction. The Ig-like domain-containing protein myotilin provides structural integrity to Z-discs-the boundaries between adjacent sarcomeres. Myotilin binds to Z-disc components, including F-actin and $\alpha$-actinin-2, but the molecular mechanism of binding and implications of these interactions on Z-disc integrity are still elusive. To illuminate them, we used a combination of small-angle X-ray scattering, cross-linking mass spectrometry, and biochemical and molecular biophysics approaches. We discovered that myotilin displays conformational ensembles in solution. We generated a structural model of the F-actin:myotilin complex that revealed how myotilin interacts with and stabilizes F-actin via its Ig-like domains and flanking regions. Mutant myotilin designed with impaired F-actin binding showed increased dynamics in cells. Structural analyses and competition assays uncovered that myotilin displaces tropomyosin from F-actin. Our findings suggest a novel role of myotilin as a co-organizer of Z-disc assembly and advance our mechanistic understanding of myotilin's structural role in Z-discs.
%0 Journal Article
%1 kostanMolecularBasisFactin2021
%A Kostan, Julius
%A Pavsic, Miha
%A Puz, Vid
%A Schwarz, Thomas C.
%A Drepper, Friedel
%A Molt, Sibylle
%A Graewert, Melissa Ann
%A Schreiner, Claudia
%A Sajko, Sara
%A van der Ven, Peter F. M.
%A Onipe, Adekunle
%A Svergun, Dmitri I.
%A Warscheid, Bettina
%A Konrat, Robert
%A Fürst, Dieter O.
%A Lenarcic, Brigita
%A Djinović-Carugo, Kristina
%C United States
%D 2021
%J PLoS biology
%K *Protein Binding/genetics,Protein Contraction/genetics,Muscle Cultured,Cytoskeletal Cytoskeleton/chemistry/genetics/metabolism,Actins/chemistry/genetics/*metabolism,Animals,Cells Domains Interaction Motifs/genetics,Sarcomeres/genetics/*metabolism,to_read,Tropomyosin/chemistry/genetics/metabolism Multimerization/genetics,Actin Proteins/chemistry/genetics/metabolism,Muscle Proteins/genetics/metabolism,Cytoskeleton/metabolism,Humans,Mice,Microfilament Skeletal/metabolism,Protein and
%N 4
%P e3001148
%R 10.1371/journal.pbio.3001148
%T Molecular Basis of F-actin Regulation and Sarcomere Assembly via Myotilin.
%V 19
%X Sarcomeres, the basic contractile units of striated muscle cells, contain arrays of thin (actin) and thick (myosin) filaments that slide past each other during contraction. The Ig-like domain-containing protein myotilin provides structural integrity to Z-discs-the boundaries between adjacent sarcomeres. Myotilin binds to Z-disc components, including F-actin and $\alpha$-actinin-2, but the molecular mechanism of binding and implications of these interactions on Z-disc integrity are still elusive. To illuminate them, we used a combination of small-angle X-ray scattering, cross-linking mass spectrometry, and biochemical and molecular biophysics approaches. We discovered that myotilin displays conformational ensembles in solution. We generated a structural model of the F-actin:myotilin complex that revealed how myotilin interacts with and stabilizes F-actin via its Ig-like domains and flanking regions. Mutant myotilin designed with impaired F-actin binding showed increased dynamics in cells. Structural analyses and competition assays uncovered that myotilin displaces tropomyosin from F-actin. Our findings suggest a novel role of myotilin as a co-organizer of Z-disc assembly and advance our mechanistic understanding of myotilin's structural role in Z-discs.
@article{kostanMolecularBasisFactin2021,
abstract = {Sarcomeres, the basic contractile units of striated muscle cells, contain arrays of thin (actin) and thick (myosin) filaments that slide past each other during contraction. The Ig-like domain-containing protein myotilin provides structural integrity to Z-discs-the boundaries between adjacent sarcomeres. Myotilin binds to Z-disc components, including F-actin and {$\alpha$}-actinin-2, but the molecular mechanism of binding and implications of these interactions on Z-disc integrity are still elusive. To illuminate them, we used a combination of small-angle X-ray scattering, cross-linking mass spectrometry, and biochemical and molecular biophysics approaches. We discovered that myotilin displays conformational ensembles in solution. We generated a structural model of the F-actin:myotilin complex that revealed how myotilin interacts with and stabilizes F-actin via its Ig-like domains and flanking regions. Mutant myotilin designed with impaired F-actin binding showed increased dynamics in cells. Structural analyses and competition assays uncovered that myotilin displaces tropomyosin from F-actin. Our findings suggest a novel role of myotilin as a co-organizer of Z-disc assembly and advance our mechanistic understanding of myotilin's structural role in Z-discs.},
added-at = {2024-05-17T13:01:35.000+0200},
address = {United States},
author = {Kostan, Julius and Pav{\v s}i{\v c}, Miha and Pu{\v z}, Vid and Schwarz, Thomas C. and Drepper, Friedel and Molt, Sibylle and Graewert, Melissa Ann and Schreiner, Claudia and Sajko, Sara and {van der Ven}, Peter F. M. and Onipe, Adekunle and Svergun, Dmitri I. and Warscheid, Bettina and Konrat, Robert and F{\"u}rst, Dieter O. and Lenar{\v c}i{\v c}, Brigita and {Djinovi{\'c}-Carugo}, Kristina},
biburl = {https://www.bibsonomy.org/bibtex/2e7bd2ce3f16d3fa1ab66bd624dd37b8c/warscheidlab},
doi = {10.1371/journal.pbio.3001148},
interhash = {f6376c3c19a2846ce2ed734340cc8d35},
intrahash = {e7bd2ce3f16d3fa1ab66bd624dd37b8c},
issn = {1545-7885 1544-9173},
journal = {PLoS biology},
keywords = {*Protein Binding/genetics,Protein Contraction/genetics,Muscle Cultured,Cytoskeletal Cytoskeleton/chemistry/genetics/metabolism,Actins/chemistry/genetics/*metabolism,Animals,Cells Domains Interaction Motifs/genetics,Sarcomeres/genetics/*metabolism,to_read,Tropomyosin/chemistry/genetics/metabolism Multimerization/genetics,Actin Proteins/chemistry/genetics/metabolism,Muscle Proteins/genetics/metabolism,Cytoskeleton/metabolism,Humans,Mice,Microfilament Skeletal/metabolism,Protein and},
langid = {english},
month = apr,
number = 4,
pages = {e3001148},
pmcid = {PMC8062120},
pmid = {33844684},
timestamp = {2024-05-17T13:01:35.000+0200},
title = {Molecular Basis of {{F-actin}} Regulation and Sarcomere Assembly via Myotilin.},
volume = 19,
year = 2021
}