Secretion of adenylate kinase 1 is required for extracellular ATP synthesis in C2C12 myotubes.
Extracellular ATP (exATP) has been known to be a critical ligand regulating skeletal muscle differentiation and contractibility. ExATP synthesis was greatly increased with the high level of adenylate kinase 1 (AK1) and ATP synthase beta during C2C12 myogenesis. The exATP synthesis was abolished by the knock-down of AK1 but not by that of ATP synthase beta in C2C12 myotubes, suggesting that AK1 is required for exATP synthesis in myotubes. However, membrane-bound AK1beta was not involved in exATP synthesis because its expression level was decreased during myogenesis in spite of its localization in the lipid rafts that contain various kinds of receptors and mediate cell signal transduction, cell migration, and differentiation. Interestingly, cytoplasmic AK1 was secreted from C2C12 myotubes but not from C2C12 myoblasts. Taken together all these data, we can conclude that AK1 secretion is required for the exATP generation in myotubes.
Choo
Hyo-Jung
HJ
School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
Kim
Bong-Woo
BW
Kwon
Oh-Bong
OB
Lee
Chang Seok
CS
Choi
Jong-Soon
JS
Ko
Young-Gyu
YG
D000255:Adenosine Triphosphate / Q000096:biosynthesis*; D000263:Adenylate Kinase / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D005110:Extracellular Space / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism*; D051379:Mice; D009132:Muscles / Q000166:cytology / Q000378:metabolism*
D007527:Isoenzymes; D000255:Adenosine Triphosphate; D000263:Adenylate Kinase; C110939:adenylate kinase 1