Muscle Metabolism 1 for attendance for lecture 1

Skeletal muscle

• activity generates body heat

• regulates urination

• provides amino acids for gluconeogenesis during the well-feed state

• facilitate digestion

The following proteins are found at the triad junction

• ryanodine receptor

• SERCA1

• Alpha Dihydropyridine receptor

• FKBP12

The alpha 1,4 Dihydropyridine receptor (DHPR) in skeletal muscles

• is activated by membrane depolarization of the t tubules.

• consists of 5 subunits.

• releases calcium into the cytosol.

• physically interacts with calsequestrin.

Tags

NGSS.HS-LS1-3

Using the drawing on the left, briefly describe the process of EC-coupling.

Dystrophin

• is the largest protein found in muscle.

• is found as dystrophin-glycoprotein complex in all muscle types

• links the contractile apparatus to the sarcolemma.

• is necessary for both muscle stiffness and mechanical stability

Myosin

• is a protein found in the thick filaments

• the whole molecule consists of 2 heavy and 4 light chains

• is directly connected to dystrophin

• can bind in total 2 ATP molecules

• binds to actin in the absence of calcium

Actin monomers called .... polymerize into a filamentous array called F-actin.

The troponin complex consists of

• TnI

• TnT

• TnC

• TnA

Tick the correct statement/s

• when the RyR opens, the cytosolic levels of Ca2+ ions increase

• Ca2+ binds to troponin C, resulting in a conformational change of the troponin-tropomysin complex

• The troponin-Ca2+ complex pulls tropomyosin away from the myosin-binding site on actin

• Myosin binds to actin and completes the power stroke which leads to a shortening of the sarcomere.

• ATP binds to actin which then detaches from myosin