BIOCHEMISTRY OF MUSCLE CONTRACTION

   This home page contains selected graduate course lectures, PHYB-BCHE 516, 1975-1997, by Michael and Kate Bárány, University of Illinois at Chicago

 Updated: March 2002

 

CONTENTS

INTRODUCTION

SKELETAL MUSCLE

Disintegration of the Muscle

Contractile Proteins

Myosin

Structure

Size and shape of the myosin molecule

Myosin light chains

Review

Function

Myosin-actin binding

ATPase activity of myosin

Separate actin-binding and ATPase sites of myosin

Intermediates of the ATP hydrolysis

ATPase activity of myosin and speed of muscle shortening

Myosin heavy chains

Three dimensional structure of subfragment 1

Structure-function relationship in myosin

Assembly
Myosin filament

Muscle fibers, myofibrils

Localization of myosin in the structure of muscle

References

Actin

The two forms of actin

Actin-myosin binding

Three dimensional structure of actin

The intersubunit contacts in the F-actin filaments

Localization of actin in the structure of muscle

Structure of the thin filament

References

Actin-Myosin Interaction

Structural model

Contact sites

Lever arm model

X-ray diffraction and electron microscopy of muscle

In vitro motility assay

References

Regulatory Proteins

Tropomyosin

Tropomyosin isoforms

Structure of tropomyosin

Binding properties

Troponin

Troponin C

Troponin I

Troponin T

References

Regulation of Muscle Contraction

The Role of Ca2+ in Regulation of Skeletal Muscle Contraction  

Historical experiments

The experiments of Huxley and Taylor

Sarcoplasmic Reticulum

Signal transduction between T-tubule and SR-junction

 Excitation-Contraction Coupling

Sequence of events
References

 Mechanism of Skeletal Muscle Contraction

The sliding filament theory

Length-tension relationship

Crossbridge cycle and its relation to actomyosin ATPase

Summary of Events in Skeletal Muscle Contraction

Excitation
 Contraction
 Relaxation
References

 Energetics

 Historical Development of Muscle Energetics

The lactic acid theory and its disproof

The Lohmann reaction and its inhibition

ATP, Phosphocreatine and Glycogen Provide Energy for Muscle Contraction

Heat Production during Muscle Contraction

The relationship between energy output and chemical breakdown

Energy Cost Assessment in Humans

Direct calorimetry

Indirect calorimetry

Relationship between work-output and O2 consumption

Oxygen debt

Adaptation to exercise

Fatigue

References

HEART MUSCLE

Basic physiology

Ultrastructure

Contractile Proteins

Myosin

Actin

Regulatory Proteins

Troponin C

Troponin I

Troponin T

Tropomyosin

Movement of the regulatory proteins in systole versus diastole

Methods

Displacement of endogenous TN in skinned fibers with TN mutants

Purification of cardiac myofibrils

Gel electrophoresis of the regulatory proteins

Literature

Regulation of Ca2+ Flow

Sarcoplasmic Reticulum

Ca2+ induced Ca2+ release

Calsequestrin

Phospholamban

Factors controlling the Ca2+ release from SR

Sarcolemma

Ca2+ sensitivity

Excitation-Contraction Coupling

Major events in cardiac E-C coupling

Biochemistry of Starling's Law

Energetics

Suggested readings

References

SMOOTH MUSCLE

Structure

Innervation and stimulation

Myofibril proteins

Phosphorylation and Dephosphorylation of the 20-kDa Myosin Light Chain

Myosin light chain kinase and myosin light chain phosphatase

Myosin light chain phosphorylation in intact smooth muscle

Isoforms of the 20-kDa myosin light chain

Phosphorylation site

Two-dimensional tryptic peptide mapping

The role of Ca2+ in light chain phosphorylation

Stretch-induced light chain phosphorylation

Phosphorylation of Heat Shock Proteins

Signal Transduction

Inositol 1,4,5-trisphosphate

G-proteins

Phosphoinoside-specific phospholipase C

The Contractile Event of Smooth Muscle

Monomer (G) to Polymer (F) Transformation of Actin in Smooth Muscle

Characteristics of the exchange of the actin-bound nucleotide in smooth muscle
References

CELL MOTILITY

Historical Development of Cell Motility

Actin-Binding Proteins

Profilin
Gelsolin
Structure and function
ADF/cofilin
Arp2/3 complex and WASp/Scar proteins
Dendritic nucleation model
Actin in the cytoskeleton

Non-Muscle Myosins

Microtubules

Kinesin and dynein
References


For more information please contact:

Michael Bárány

Department of Biochemistry and Molecular Biology (M/C 536)

University of Illinois at Chicago

Chicago, IL 60612-7334

mailto:mbarany@uic.edu