Probing the Difference in Myosin Light Chain Kinase Expression between Older and Young Adults

Presenter: Cole Jilek

Faculty Sponsor: Mark S. Miller

School: UMass Amherst

Research Area: Medical Sciences

Session: Poster Session 6, 4:15 PM - 5:00 PM, 163, C25

ABSTRACT

After the age of 60 years old, the ability of the body’s muscles to generate power decreases by 1.2% per year, leading to difficulty performing activities of daily living and increased mortality due to falls and low levels of physical activity. This decrease in muscle function is associated with changes at the molecular level. Specifically, the interactions between myosin, the force producing protein in skeletal muscle, and actin filaments slow, which reduces single fiber contractile velocity and causes slower movements in older adults. Myosin regulatory light chain (RLC), a protein that binds to the neck region of myosin and can be phosphorylated to enhance actin-myosin interactions, is less phosphorylated in older adults, especially females. This reduced phosphorylation leads to fewer myosin heads being close to their actin binding partner, causing decreased muscle fiber force and velocity. Why RLC phosphorylation is reduced in older adults is currently unknown. My research seeks to quantify the amount of myosin light chain kinase (MLCK), which phosphorylates the RLC, in the skeletal muscle of older and young adults by using gel electrophoresis, which separates the various proteins in a muscle cell by size and charge, then performing a western blot, which uses MLCK-specific antibodies to visualize the protein. We hypothesize that aging muscle has decreased MLCK expression leading to decreased RLC phosphorylation. Resolving the cause of the decrease in RLC phosphorylation with age will provide insight into maintaining muscular function with age and may identify a therapeutic intervention to combat muscular aging.

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