Ontology highlight
ABSTRACT: This model is described in the article: Abstract: ARPP-16, ARPP-19, and ENSA are inhibitors of protein phosphatase PP2A. ARPP-19 and ENSA phosphorylated by Greatwall kinase inhibit PP2A during mitosis. ARPP-16 is expressed in striatal neurons where basal phosphorylation by MAST3 kinase inhibits PP2A and regulates key components of striatal signaling. The ARPP-16/19 proteins were discovered as substrates for PKA, but the function of PKA phosphorylation is unknown. We find that phosphorylation by PKA or MAST3 mutually suppresses the ability of the other kinase to act on ARPP-16. Phosphorylation by PKA also acts to prevent inhibition of PP2A by ARPP-16 phosphorylated by MAST3. Moreover, PKA phosphorylates MAST3 at multiple sites resulting in its inhibition. Mathematical modeling highlights the role of these three regulatory interactions to create a switch-like response to cAMP. Together, the results suggest a complex antagonistic interplay between the control of ARPP-16 by MAST3 and PKA that creates a mechanism whereby cAMP mediates PP2A disinhibition. This model is hosted on BioModels Database and identified by: BIOMD0000000644. To cite BioModels Database, please use: Chelliah V et al. BioModels: ten-year anniversary. Nucl. Acids Res. 2015, 43(Database issue):D542-8. To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information.
ORGANISM(S): Mus sp.
SUBMITTER: Lucian Smith
PROVIDER: MODEL1707020001 | biostudies-other |
SECONDARY ACCESSION(S): 10.7554/eLife.24998
REPOSITORIES: biostudies-other

FEBS letters 20150212 6
To facilitate rapid accumulation of Cdk1-phosphorylated substrate proteins, the Cdk1 counter-acting phosphatase, PP2A-B55 is inhibited during M phase by stoichiometric inhibitors (ENSA and Arpp19). These inhibitors are activated when phosphorylated by Cdk1-activated Greatwall-kinase. Recent experiments show that ENSA is dephosphorylated and inactivated by the PP2A-B55 itself, and acts as an unfair substrate inhibiting PP2A-B55 activity towards other Cdk1 substrates. Mathematical modelling shows ...[more]