molecular cell biology
DESCRIPTION
Molecular Cell Biology. Myosin Cooper. Diagram of a Sarcomere. Sliding Filament Model: Length-Tension Relationship. Physiological Part of the Curve. Tension (Force produced by Muscle Contraction). Length (of the Sarcomere). Myosin Moving on Actin Filament in Muscle. - PowerPoint PPT PresentationTRANSCRIPT
Molecular Cell Biology
Myosin
Cooper
Diagram of a Sarcomere
Sliding Filament Model: Length-Tension Relationship
Length (of the Sarcomere)
Tension(Forceproducedby MuscleContraction)
Physiological Part of the Curve
Myosin Moving on Actin Filament in Muscle
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ActoMyosin Cycle:ATP Hydrolysis &
Movement
Structure of Myosin Head & Neck
Evidence for Twisting Head Model:Myosin Lever Arm Orientations
Thin Filament Proteins Drawn to Scale
Tropomyosin
Actin
Troponin
Simple Steric Blocking Model
Tm
Ac
Ac
Myosin
Myosin
Tm
Ac
Ac
Off
On
Familial Hypertrophic Cardiomyopathy
Inherited human disease• Heart dysfunction and sudden death
Autosomal dominant Myosin heavy chain gene first Other sarcomere components Subtle mutations
• Mild effects on Biochemical Function
Myosin: Definitions
Biochemical: Actin-activated ATPase
Mechanical: Moves along actin filament
Structural: Conserved motor domain, with
binding sites for actin and ATP
Structural Regions of Myosins
Phylogenetic Tree of
Myosins
Myosin II: Contraction Bipolar Filaments Stress Fibers Contractile Ring of Cytokinesis Tail Contraction in Cell Migration
• Toothpaste Tube Model Epithelial Cells
• Folding a Layer in Development• Apoptosis - Extruding a Cell
Myosin-V: Hand-over-hand Processivity
Myosin-V: Molecular Movement
Atomic Force Microscopy
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Atomic Force Microscopy
Tapping Mode
Myosin V Auto-Inhibition
Myosin V in Budding Yeast
Tracks of Actin Filaments...•Anchored via Barbed Ends•At Specific Locations on the Plasma Membrane (1)•Filaments Bundled (2)
Myosin V in Budding Yeast
Cargos for the Myosin...•Secretory Vesicles for Polarized Growth (3)•Distal Plus Ends of Mts, to Position the Mitotic Spindle (4)•mRNA to Specify Daughter-Cell Property (5)•Inheritance / Segregation of Organelles, e.g. Vacuole/Lysosome (6)
Moves Backward - Toward Pointed End Motor domain has insertion sequence in position
similar to an insertion in Ncd, the backwards kinesin
Associated w/ Unusual Actin Filament Structures during Spermatogenesis in Drosophila and C. elegans
Myosin VI
Hair Cell Sound Adaptation and Myo1c
Control After Intense Sound
Tip Links by Scanning EM: Effect of Sound
External Swf Files
Channel Gating Positive adaptation Negative adaptation
Myosin Isoform Localization
Ic VI VIIa
Myo1c Localizationby ImmunoEM
NMB-ADP Analogue Strategyfor Inhibiting an ATPase
Electrophysiology Results
Model
Wild-type Mutant
End