CDAE 158 Lecture Notes - Lecture 13: Globular Protein, Actin, Myasthenia Gravis
12 Oct 2018
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Document Summary
Assembled from bundles of protein molecules, myosin. Each myosin protein has two intertwined strands. Each strand has globular head and elongated tail. Tails pointing toward center of thick filaments. Heads pointing toward edges of thick filaments. Head with a binding site for actin (on thin filaments) Composed primarily of two strands of actin. Actin strands composed of spherical molecules, globular actin. Connect to form a fibrous strand, filamentous actin. G-actin has myosin binding site- where myosin head attaches during contraction. Covers myosin binding sites in non-contracting muscle. How does the sliding filament model work: the fiber must be stimulated by a nerve, the fiber must generate an action potential, the action potential must propagate along the sarcolemma. Intracellular calcium must be released to trigger contraction. 3 major phases of skeletal muscle contraction: neuromuscular contraction, excitation-contraction coupling, cross-bridge cycling. Autoimmune disease, commonly impacting women under 40 and men over 60. Antibody binding causes receptors to be removed from the plasma membrane.
