TY - JOUR
T1 - Activation of PASK by mTORC1 is required for the onset of the terminal differentiation program
AU - Kikani, Chintan K.
AU - Wu, Xiaoying
AU - Fogarty, Sarah
AU - Kang, Seong Anthony Woo
AU - Dephoure, Noah
AU - Gygi, Steven P.
AU - Sabatini, David M.
AU - Rutter, Jared
N1 - Publisher Copyright:
© 2019 National Academy of Sciences. All rights reserved.
PY - 2019
Y1 - 2019
N2 - During skeletal muscle regeneration, muscle stem cells (MuSCs) respond to multiple signaling inputs that converge onto mammalian target of rapamycin complex 1 (mTORC1) signaling pathways. mTOR function is essential for establishment of the differentiationcommitted progenitors (early stage of differentiation, marked by the induction of myogenin expression), myotube fusion, and, ultimately, hypertrophy (later stage of differentiation). While a major mTORC1 substrate, p70S6K, is required for myotube fusion and hypertrophy, an mTORC1 effector for the induction of myogenin expression remains unclear. Here, we identified Per-Arnt-Sim domain kinase (PASK) as a downstream phosphorylation target ofmTORC1 in MuSCs during differentiation. We have recently shown that the PASK phosphorylates Wdr5 to stimulate MuSC differentiation by epigenetically activating the myogenin promoter. We show that phosphorylation of PASK by mTORC1 is required for the activation of myogenin transcription, exit from self-renewal, and induction of the myogenesis program. Our studies reveal that mTORC1-PASK signaling is required for the rise of myogenin-positive committed myoblasts (early stage of myogenesis), whereas mTORC1-S6K signaling is required for myoblast fusion (later stage of myogenesis). Thus, our discoveries allow molecular dissection of mTOR functions during different stages of the myogenesis program driven by two different substrates.
AB - During skeletal muscle regeneration, muscle stem cells (MuSCs) respond to multiple signaling inputs that converge onto mammalian target of rapamycin complex 1 (mTORC1) signaling pathways. mTOR function is essential for establishment of the differentiationcommitted progenitors (early stage of differentiation, marked by the induction of myogenin expression), myotube fusion, and, ultimately, hypertrophy (later stage of differentiation). While a major mTORC1 substrate, p70S6K, is required for myotube fusion and hypertrophy, an mTORC1 effector for the induction of myogenin expression remains unclear. Here, we identified Per-Arnt-Sim domain kinase (PASK) as a downstream phosphorylation target ofmTORC1 in MuSCs during differentiation. We have recently shown that the PASK phosphorylates Wdr5 to stimulate MuSC differentiation by epigenetically activating the myogenin promoter. We show that phosphorylation of PASK by mTORC1 is required for the activation of myogenin transcription, exit from self-renewal, and induction of the myogenesis program. Our studies reveal that mTORC1-PASK signaling is required for the rise of myogenin-positive committed myoblasts (early stage of myogenesis), whereas mTORC1-S6K signaling is required for myoblast fusion (later stage of myogenesis). Thus, our discoveries allow molecular dissection of mTOR functions during different stages of the myogenesis program driven by two different substrates.
KW - MTOR
KW - Muscle stem cell
KW - Myogenin
KW - PASK
KW - Pax7
UR - http://www.scopus.com/inward/record.url?scp=85066099262&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85066099262&partnerID=8YFLogxK
U2 - 10.1073/pnas.1804013116
DO - 10.1073/pnas.1804013116
M3 - Article
C2 - 31072927
AN - SCOPUS:85066099262
SN - 0027-8424
VL - 116
SP - 10382
EP - 10391
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 21
ER -