TY - JOUR
T1 - Kinetic Regulation of the Mammalian Sterile 20-like Kinase 2 (MST2)
AU - Koehler, Thomas J.
AU - Tran, Thao
AU - Weingartner, Kyler A.
AU - Kavran, Jennifer M.
N1 - Publisher Copyright:
© 2022 American Chemical Society.
PY - 2022/8/16
Y1 - 2022/8/16
N2 - Canonically, MST1/2 functions as a core kinase of the Hippo pathway and noncanonically during both apoptotic signaling and with RASSFs in T-cells. Faithful signal transduction by MST1/2 relies on both appropriate activation and regulated substrate phosphorylation by the activated kinase. Considerable progress has been made in understanding the molecular mechanisms regulating the activation of MST1/2 and identifying downstream signaling events. Here, we investigated the ability of MST2 to phosphorylate a peptide substrate and how that activity is regulated. Using a steady-state kinetic system, we parse the contribution of different factors to substrate phosphorylation, including the domains of MST2, phosphorylation, caspase cleavage, and complex formation. We found that in the unphosphorylated state, the SARAH domain stabilizes interactions with a peptide substrate and promotes turnover. Phosphorylation drives the activity of MST2, and once activated, MST2 is not further regulated by complex formation with other Hippo pathway components (SAV1, MOB1A, and RASSF5). We also show that the phosphorylated, caspase-cleaved MST2 is as active as the full-length one, suggesting that caspase-stimulated activity arises through noncatalytic mechanisms. The kinetic analysis presented here establishes a framework for interpreting how signaling events and post-translational modifications contribute to the signaling of MST2 in vivo.
AB - Canonically, MST1/2 functions as a core kinase of the Hippo pathway and noncanonically during both apoptotic signaling and with RASSFs in T-cells. Faithful signal transduction by MST1/2 relies on both appropriate activation and regulated substrate phosphorylation by the activated kinase. Considerable progress has been made in understanding the molecular mechanisms regulating the activation of MST1/2 and identifying downstream signaling events. Here, we investigated the ability of MST2 to phosphorylate a peptide substrate and how that activity is regulated. Using a steady-state kinetic system, we parse the contribution of different factors to substrate phosphorylation, including the domains of MST2, phosphorylation, caspase cleavage, and complex formation. We found that in the unphosphorylated state, the SARAH domain stabilizes interactions with a peptide substrate and promotes turnover. Phosphorylation drives the activity of MST2, and once activated, MST2 is not further regulated by complex formation with other Hippo pathway components (SAV1, MOB1A, and RASSF5). We also show that the phosphorylated, caspase-cleaved MST2 is as active as the full-length one, suggesting that caspase-stimulated activity arises through noncatalytic mechanisms. The kinetic analysis presented here establishes a framework for interpreting how signaling events and post-translational modifications contribute to the signaling of MST2 in vivo.
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U2 - 10.1021/acs.biochem.2c00022
DO - 10.1021/acs.biochem.2c00022
M3 - Article
C2 - 35895874
AN - SCOPUS:85136143013
SN - 0006-2960
VL - 61
SP - 1683
EP - 1693
JO - Biochemistry
JF - Biochemistry
IS - 16
ER -