Perazza, L.R.Wei, G.Thompson, L.V.2023-10-122023-10-122023-04L.R. Perazza, G. Wei, L.V. Thompson. 2023. "Fast and slow skeletal myosin binding protein-C and aging." GeroScience, Volume 45, Issue 2, pp.915-929. https://doi.org/10.1007/s11357-022-00689-y2509-27152509-2723https://hdl.handle.net/2144/46931Aging is associated with skeletal muscle strength decline and cardiac diastolic dysfunction. The structural arrangements of the sarcomeric proteins, such as myosin binding protein-C (MyBP-C) are shown to be pivotal in the pathogenesis of diastolic dysfunction. Yet, the role of fast (fMyBP-C) and slow (sMyBP-C) skeletal muscle MyBP-C remains to be elucidated. Herein, we aimed to characterize MyBP-C and its paralogs in the fast tibialis anterior (TA) muscle from adult and old mice. Immunoreactivity preparations showed that the relative abundance of the fMyBP-C paralog was greater in the TA of both adult and old, but no differences were noted between groups. We further found that the expression level of cardiac myosin binding protein-C (cMyBP-C), an important modulator of cardiac output, was lowered by age. Standard SDS-PAGE along with Pro-Q Diamond phosphoprotein staining did not identify age-related changes in phosphorylated MyBP-C proteins from TA and cardiac muscles; however, it revealed that MyBP-C paralogs in fast skeletal and cardiac muscle were highly phosphorylated. Mass spectrometry further identified glycogen phosphorylase, desmin, actin, troponin T, and myosin regulatory light chain 2 as phosphorylated myofilament proteins in both ages. MyBP-C protein-bound carbonyls were determined using anti-DNP immunostaining and found the carbonyl level of fMyBP-C, sMyBP-C, and cMyBP-C to be similar between old and adult animals. In summary, our data showed some differences regarding the MyBP-C paralog expression and identified an age-related reduction of cMyBP-C expression. Future studies are needed to elucidate which are the age-driven post-translational modifications in the MyBP-C paralogs.915-929Print-Electronicen© The Author(s) 2022. This article is distributed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0).http://creativecommons.org/licenses/by/4.0/AgingMuscle contractilityPhosphorylationMiceAnimalsMyocardiumMuscle, skeletalMyosinsAgingArticle2023-03-0610.1007/s11357-022-00689-y0000-0002-6481-9029 (Thompson, LV)768407