The M-phase regulatory phosphatase PP2A-B55d opposes protein kinase A on Arpp19 to initiate meiotic division

Tom Lemonnier, Enrico Maria Daldello, Robert Poulhe, Tran Le, Marika Miot, Catherine Jessus, Aude Dupré

Like 0 Comment

Received Date: 22nd October 19

Oocytes are held in meiotic prophase for prolonged periods until hormonal signals trigger meiotic divisions. Key players of M-phase entry are the opposing Cdk1 kinase and PP2A-B55d phosphatase. In Xenopus, the protein Arpp19, phosphorylated at serine 67 by Greatwall, plays an essential role in inhibiting PP2A-B55d, promoting Cdk1 activation. Furthermore Arpp19 has an earlier role in maintaining the prophase arrest through a second serine (S109) phosphorylated by PKA. Prophase release, induced by progesterone, relies on Arpp19 dephosphorylation at S109, owing to an unknown phosphatase. Here we identified this phosphatase as PP2A-B55d. In prophase, PKA and PP2A-B55d are simultaneously active, suggesting the presence of other important targets for both enzymes. The drop in PKA activity induced by progesterone enables PP2A-B55d to dephosphorylate S109, unlocking the prophase block. Hence, PP2A-B55d acts critically on Arpp19 on two distinct sites, opposing PKA and Greatwall to orchestrate the prophase release and M-phase entry.

Read in full at bioRxiv.

This is an abstract of a preprint hosted on an independent third party site. It has not been peer reviewed but is currently under consideration at Nature Communications.

Go to the profile of Nature Communications

Nature Communications

Nature Research, Springer Nature