TY - JOUR
T1 - Phosphorylation of αB-crystallin and its cytoskeleton association differs in skeletal myofiber types depending on resistance exercise intensity and volume
AU - Jacko, Daniel
AU - Bersiner, Käthe
AU - Hebchen, Jonas
AU - de Marées, Markus
AU - Bloch, Wilhelm
AU - Gehlert, Sebastian
PY - 2019/6
Y1 - 2019/6
N2 - αB-crystallin (CRYAB) is an important actor in the immediate cell stabilizing response following mechanical stress in skeletal muscle. Yet, only little is known regarding myofiber type-specific stress responses of CRYAB. We investigated whether the phosphorylation of CRYAB at serine 59 (pCRYABSer59) and its cytoskeleton association are influenced by varying load-intensity and -volume in a fiber type-specific manner. Male subjects were assigned to 1, 5, and 10 sets of different acute resistance exercise protocols: hypertrophy (HYP), maximum strength (MAX), strength endurance (SE), low intensity (LI), and three sets of maximum eccentric resistance exercise (ECC). Skeletal muscle biopsies were taken at baseline and 30 min after exercise. Western blot revealed an increase in pCRYABSer59 only following 5 and 10 sets in groups HYP, MAX, SE, and LI as well as following 3 sets in the ECC group. In type I fibers, immunohistochemistry determined increased pCRYABSer59 in all groups. In type II fibers, pCRYABSer59 only increased in MAX and ECC groups, with the increase in type II fibers exceeding that of type I fibers in ECC. Association of CRYAB and pCRYABSer59 with the cytoskeleton reflected the fiber type-specific phosphorylation pattern. Phosphorylation of CRYAB and its association with the cytoskeleton in type I and II myofibers is highly specific in terms of loading intensity and volume. Most likely, this is based on specific recruitment patterns of the different myofiber entities due to the different resistance exercise loadings. We conclude that pCRYABSer59 indicates contraction-induced mechanical stress exposure of single myofibers in consequence of resistance exercise. NEW & NOTEWORTHY We determined that the phosphorylation of αB-crystallin at serine 59 (pCRYABSer59) after resistance exercise differs between myofiber types in a load- and intensity-dependent manner. The determination of pCRYABSer59 could serve as a marker indirectly indicating contractile involvement and applied mechanical stress on individual fibers. By that, it is possible to retrospectively assess the impact of resistance exercise loading on skeletal muscle fiber entities.
AB - αB-crystallin (CRYAB) is an important actor in the immediate cell stabilizing response following mechanical stress in skeletal muscle. Yet, only little is known regarding myofiber type-specific stress responses of CRYAB. We investigated whether the phosphorylation of CRYAB at serine 59 (pCRYABSer59) and its cytoskeleton association are influenced by varying load-intensity and -volume in a fiber type-specific manner. Male subjects were assigned to 1, 5, and 10 sets of different acute resistance exercise protocols: hypertrophy (HYP), maximum strength (MAX), strength endurance (SE), low intensity (LI), and three sets of maximum eccentric resistance exercise (ECC). Skeletal muscle biopsies were taken at baseline and 30 min after exercise. Western blot revealed an increase in pCRYABSer59 only following 5 and 10 sets in groups HYP, MAX, SE, and LI as well as following 3 sets in the ECC group. In type I fibers, immunohistochemistry determined increased pCRYABSer59 in all groups. In type II fibers, pCRYABSer59 only increased in MAX and ECC groups, with the increase in type II fibers exceeding that of type I fibers in ECC. Association of CRYAB and pCRYABSer59 with the cytoskeleton reflected the fiber type-specific phosphorylation pattern. Phosphorylation of CRYAB and its association with the cytoskeleton in type I and II myofibers is highly specific in terms of loading intensity and volume. Most likely, this is based on specific recruitment patterns of the different myofiber entities due to the different resistance exercise loadings. We conclude that pCRYABSer59 indicates contraction-induced mechanical stress exposure of single myofibers in consequence of resistance exercise. NEW & NOTEWORTHY We determined that the phosphorylation of αB-crystallin at serine 59 (pCRYABSer59) after resistance exercise differs between myofiber types in a load- and intensity-dependent manner. The determination of pCRYABSer59 could serve as a marker indirectly indicating contractile involvement and applied mechanical stress on individual fibers. By that, it is possible to retrospectively assess the impact of resistance exercise loading on skeletal muscle fiber entities.
KW - B-crystallin
KW - Fiber types
KW - Resistance exercise
KW - Skeletal muscle
KW - Small heat shock proteins
UR - https://www.mendeley.com/catalogue/56e98239-13e0-38d7-9b59-36629f39b755/
U2 - 10.1152/japplphysiol.01038.2018
DO - 10.1152/japplphysiol.01038.2018
M3 - Journal articles
SN - 8750-7587
VL - 126
SP - 1607
EP - 1618
JO - Journal of applied physiology (Bethesda, Md. : 1985)
JF - Journal of applied physiology (Bethesda, Md. : 1985)
IS - 6
ER -