Fast and slow skeletal myosin binding protein-C and aging

Area of Science:

• Muscle physiology
• Cardiovascular research
• Aging studies

Background:

• Aging is linked to decreased skeletal muscle strength and cardiac diastolic dysfunction.
• Myosin binding protein-C (MyBP-C) is crucial in diastolic dysfunction pathogenesis.
• The specific roles of fast (fMyBP-C) and slow (sMyBP-C) skeletal muscle MyBP-C in aging are not fully understood.

Purpose of the Study:

• To characterize MyBP-C and its paralogs in the fast tibialis anterior (TA) muscle of adult and old mice.
• To investigate age-related changes in MyBP-C expression and phosphorylation.
• To explore the impact of aging on MyBP-C protein oxidation.

Main Methods:

• Immunoreactivity staining to assess MyBP-C paralog abundance in TA muscle.
• SDS-PAGE and Pro-Q Diamond phosphoprotein staining to analyze MyBP-C phosphorylation.
• Mass spectrometry to identify phosphorylated myofilament proteins.
• Anti-DNP immunostaining to quantify MyBP-C protein carbonyl levels.

Main Results:

• The relative abundance of fMyBP-C was higher in TA muscle of both adult and old mice, with no significant differences between age groups.
• Cardiac myosin binding protein-C (cMyBP-C) expression decreased with age.
• No age-related changes were found in phosphorylated MyBP-C levels or MyBP-C protein carbonyls.
• MyBP-C paralogs in fast skeletal and cardiac muscle were highly phosphorylated, with other myofilament proteins also showing phosphorylation.

Conclusions:

• Aging affects MyBP-C paralog expression, notably reducing cMyBP-C levels.
• While MyBP-C phosphorylation and oxidation showed no age-related differences in this study, further research is needed.
• Future studies should focus on identifying age-driven post-translational modifications of MyBP-C paralogs.