The study of the determinants controlling Arpp19 phosphatase-inhibitory activity reveals an Arpp19/PP2A-B55 feedback loop

Jean Claude Labbé (1) , Suzanne Vigneron (1) , Francisca Méchali (1) , Perle Robert (1) , Sylvain Roque (1) , Cindy Genoud (1) , Perrine Goguet-Rubio (1) , Phillipe Barthe (2) , Gilles Labesse (2) , Martin Cohen-Gonsaud (2) , Anna Castro (1) , Thierry Lorca (1)

1 CRBM - Centre de recherche en Biologie cellulaire de Montpellier
2 CBS - Centre de Biochimie Structurale [Montpellier]

Abstract Arpp19 is a potent PP2A-B55 inhibitor that regulates this phosphatase to ensure the stable phosphorylation of mitotic/meiotic substrates. At G2-M, Arpp19 is phosphorylated by the Greatwall kinase on S67. This phosphorylated Arpp19 form displays a high affinity to PP2A-B55 and a slow dephosphorylation rate, acting as a competitor of PP2A-B55 substrates. The molecular determinants conferring slow dephosphorylation kinetics to S67 are unknown. PKA also phosphorylates Arpp19. This phosphorylation performed on S109 is essential to maintain prophase I-arrest in Xenopus oocytes although the underlying signalling mechanism is elusive. Here, we characterize the molecular determinants conferring high affinity and slow dephosphorylation to S67 and controlling PP2A-B55 inhibitory activity of Arpp19. Moreover, we show that phospho-S109 restricts S67 phosphorylation by increasing its catalysis by PP2A-B55. Finally, we discover a double feed-back loop between these two phospho-sites essential to coordinate the temporal pattern of Arpp19-dependent PP2A-B55 inhibition and Cyclin B/Cdk1 activation during cell division.

Domains: Life Sciences [q-bio]

Jean Claude Labbé, Suzanne Vigneron, Francisca Méchali, Perle Robert, Sylvain Roque, et al.. The study of the determinants controlling Arpp19 phosphatase-inhibitory activity reveals an Arpp19/PP2A-B55 feedback loop. Nature Communications, 2021, 12 (1), ⟨10.1038/s41467-021-23657-0⟩. ⟨hal-03263787⟩