The masticatory contractile load induced expression and activation of Akt1/PKBalpha in muscle fibers at the myotendinous junction within muscle-tendon-bone unit.
The cell specific detection of enzyme activation in response to the physiological contractile load within muscle-tendon-bone unit is essential for understanding of the mechanical forces transmission from muscle cells via tendon to the bone. The hypothesis that the physiological mechanical loading regulates activation of Akt1/PKBalpha at Thr308 and at Ser473 in muscle fibers within muscle-tendon-bone unit was tested using quantitative immunohistochemistry, confocal double fluorescence analysis, and immunoblot analysis. In comparison to the staining intensities in peripheral regions of the muscle fibers, Akt1/PKBalpha was detected with a higher staining intensity in muscle fibers at the myotendinous junction (MTJ) areas. In muscle fibers at the MTJ areas, Akt1/PKBalpha is dually phosphorylated at Thr308 and Ser473. The immunohistochemical results were confirmed by immunoblot analysis. We conclude that contractile load generated by masticatory muscles induces local domain-dependent expression of Akt1/PKBalpha as well as activation by dually phosphorylation at Thr308 and Ser473 in muscle fibers at the MTJ areas within muscle-tendon-bone unit.
Korkmaz
Yüksel
Y
Department of Operative Dentistry, Periodontics and Endodontics, Heinrich-Heine-University, 40225 Düsseldorf, Germany.
Klinz
Franz J
FJ
Moghbeli
Mehrnoush
M
Addicks
Klaus
K
Raab
Wolfgang H-M
WH
Bloch
Wilhelm
W
D000818:Animals; D001842:Bone and Bones / Q000201:enzymology* / Q000502:physiology; D015151:Immunoblotting; D007150:Immunohistochemistry; D008297:Male; D008410:Masticatory Muscles / Q000201:enzymology* / Q000502:physiology*; D009119:Muscle Contraction / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000201:enzymology* / Q000502:physiology; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D010769:Phosphothreonine / Q000378:metabolism; D021381:Protein Transport; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013710:Tendons / Q000201:enzymology* / Q000502:physiology; D016474:Weight-Bearing
D010769:Phosphothreonine; D010768:Phosphoserine; D051057:Proto-Oncogene Proteins c-akt
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