No difference in myosin kinetics and spatial distribution of the lever arm in the left and right ventricles of human hearts

Divya Duggal, S. Requena, Janhavi Nagwekar, Sangram Limbaji Raut, Ryan Rich, Hriday Das, Vipul Patel, Ignacy Gryczynski, Rafal Fudala, Zygmunt Gryczynski, Cheavar Blair, Kenneth S. Campbell, Julian Borejdo

Research output: Contribution to journalArticleResearchpeer-review

Abstract

The systemic circulation offers larger resistance to the blood flow than the pulmonary system. Consequently, the left ventricle (LV) must pump blood with more force than the right ventricle (RV). The question arises whether the stronger pumping action of the LV is due to a more efficient action of left ventricular myosin, or whether it is due to the morphological differences between ventricles. Such a question cannot be answered by studying the entire ventricles or myocytes because any observed differences would be wiped out by averaging the information obtained from trillions of myosin molecules present in a ventricle or myocyte. We therefore searched for the differences between single myosin molecules of the LV and RV of failing hearts In-situ. We show that the parameters that define the mechanical characteristics of working myosin (kinetic rates and the distribution of spatial orientation of myosin lever arm) were the same in both ventricles. These results suggest that there is no difference in the way myosin interacts with thin filaments in myocytes of failing hearts, and suggests that the difference in pumping efficiencies are caused by interactions between muscle proteins other than myosin or that they are purely morphological.

Original languageEnglish
Article number732
JournalFrontiers in Physiology
Volume8
Issue numberOCT
DOIs
StatePublished - 13 Oct 2017

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Myosins
Heart Ventricles
Muscle Cells
Ventricular Myosins
Muscle Proteins
Lung

Keywords

  • Cross-bridge orientation
  • Fluorescence polarization
  • Heart ventricles

Cite this

@article{cbd2995747b0450388cf3230e8156a9f,
title = "No difference in myosin kinetics and spatial distribution of the lever arm in the left and right ventricles of human hearts",
abstract = "The systemic circulation offers larger resistance to the blood flow than the pulmonary system. Consequently, the left ventricle (LV) must pump blood with more force than the right ventricle (RV). The question arises whether the stronger pumping action of the LV is due to a more efficient action of left ventricular myosin, or whether it is due to the morphological differences between ventricles. Such a question cannot be answered by studying the entire ventricles or myocytes because any observed differences would be wiped out by averaging the information obtained from trillions of myosin molecules present in a ventricle or myocyte. We therefore searched for the differences between single myosin molecules of the LV and RV of failing hearts In-situ. We show that the parameters that define the mechanical characteristics of working myosin (kinetic rates and the distribution of spatial orientation of myosin lever arm) were the same in both ventricles. These results suggest that there is no difference in the way myosin interacts with thin filaments in myocytes of failing hearts, and suggests that the difference in pumping efficiencies are caused by interactions between muscle proteins other than myosin or that they are purely morphological.",
keywords = "Cross-bridge orientation, Fluorescence polarization, Heart ventricles",
author = "Divya Duggal and S. Requena and Janhavi Nagwekar and Raut, {Sangram Limbaji} and Ryan Rich and Hriday Das and Vipul Patel and Ignacy Gryczynski and Rafal Fudala and Zygmunt Gryczynski and Cheavar Blair and Campbell, {Kenneth S.} and Julian Borejdo",
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language = "English",
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No difference in myosin kinetics and spatial distribution of the lever arm in the left and right ventricles of human hearts. / Duggal, Divya; Requena, S.; Nagwekar, Janhavi; Raut, Sangram Limbaji; Rich, Ryan; Das, Hriday; Patel, Vipul; Gryczynski, Ignacy; Fudala, Rafal; Gryczynski, Zygmunt; Blair, Cheavar; Campbell, Kenneth S.; Borejdo, Julian.

In: Frontiers in Physiology, Vol. 8, No. OCT, 732, 13.10.2017.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - No difference in myosin kinetics and spatial distribution of the lever arm in the left and right ventricles of human hearts

AU - Duggal, Divya

AU - Requena, S.

AU - Nagwekar, Janhavi

AU - Raut, Sangram Limbaji

AU - Rich, Ryan

AU - Das, Hriday

AU - Patel, Vipul

AU - Gryczynski, Ignacy

AU - Fudala, Rafal

AU - Gryczynski, Zygmunt

AU - Blair, Cheavar

AU - Campbell, Kenneth S.

AU - Borejdo, Julian

PY - 2017/10/13

Y1 - 2017/10/13

N2 - The systemic circulation offers larger resistance to the blood flow than the pulmonary system. Consequently, the left ventricle (LV) must pump blood with more force than the right ventricle (RV). The question arises whether the stronger pumping action of the LV is due to a more efficient action of left ventricular myosin, or whether it is due to the morphological differences between ventricles. Such a question cannot be answered by studying the entire ventricles or myocytes because any observed differences would be wiped out by averaging the information obtained from trillions of myosin molecules present in a ventricle or myocyte. We therefore searched for the differences between single myosin molecules of the LV and RV of failing hearts In-situ. We show that the parameters that define the mechanical characteristics of working myosin (kinetic rates and the distribution of spatial orientation of myosin lever arm) were the same in both ventricles. These results suggest that there is no difference in the way myosin interacts with thin filaments in myocytes of failing hearts, and suggests that the difference in pumping efficiencies are caused by interactions between muscle proteins other than myosin or that they are purely morphological.

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