1
|
Lacroix B, Vigneron S, Labbé JC, Pintard L, Lionne C, Labesse G, Castro A, Lorca T. Increases in cyclin A/Cdk activity and in PP2A-B55 inhibition by FAM122A are key mitosis-inducing events. EMBO J 2024; 43:993-1014. [PMID: 38378890 PMCID: PMC10943098 DOI: 10.1038/s44318-024-00054-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 01/31/2024] [Accepted: 02/06/2024] [Indexed: 02/22/2024] Open
Abstract
Entry into mitosis has been classically attributed to the activation of a cyclin B/Cdk1 amplification loop via a partial pool of this kinase becoming active at the end of G2 phase. However, how this initial pool is activated is still unknown. Here we discovered a new role of the recently identified PP2A-B55 inhibitor FAM122A in triggering mitotic entry. Accordingly, depletion of the orthologue of FAM122A in C. elegans prevents entry into mitosis in germline stem cells. Moreover, data from Xenopus egg extracts strongly suggest that FAM122A-dependent inhibition of PP2A-B55 could be the initial event promoting mitotic entry. Inhibition of this phosphatase allows subsequent phosphorylation of early mitotic substrates by cyclin A/Cdk, resulting in full cyclin B/Cdk1 and Greatwall (Gwl) kinase activation. Subsequent to Greatwall activation, Arpp19/ENSA become phosphorylated and now compete with FAM122A, promoting its dissociation from PP2A-B55 and taking over its phosphatase inhibition role until the end of mitosis.
Collapse
Affiliation(s)
- Benjamin Lacroix
- Université de Montpellier, Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, 1919 Route de Mende, 34293, Montpellier cedex 5, France
- Programme équipes Labellisées Ligue Contre le Cancer, Paris, France
| | - Suzanne Vigneron
- Université de Montpellier, Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, 1919 Route de Mende, 34293, Montpellier cedex 5, France
- Programme équipes Labellisées Ligue Contre le Cancer, Paris, France
| | - Jean Claude Labbé
- Université de Montpellier, Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, 1919 Route de Mende, 34293, Montpellier cedex 5, France
- Programme équipes Labellisées Ligue Contre le Cancer, Paris, France
| | - Lionel Pintard
- Programme équipes Labellisées Ligue Contre le Cancer, Paris, France
- Université Paris Cité, Institut Jacques Monod, F-75013, Paris, France
| | - Corinne Lionne
- Centre de Biologie Structurale (CBS), CNRS, INSERM, Montpellier University, Montpellier, France
| | - Gilles Labesse
- Centre de Biologie Structurale (CBS), CNRS, INSERM, Montpellier University, Montpellier, France
| | - Anna Castro
- Université de Montpellier, Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, 1919 Route de Mende, 34293, Montpellier cedex 5, France.
- Programme équipes Labellisées Ligue Contre le Cancer, Paris, France.
| | - Thierry Lorca
- Université de Montpellier, Centre de Recherche en Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, 1919 Route de Mende, 34293, Montpellier cedex 5, France.
- Programme équipes Labellisées Ligue Contre le Cancer, Paris, France.
| |
Collapse
|
2
|
Goguet-Rubio P, Amin P, Awal S, Vigneron S, Charrasse S, Mechali F, Labbé JC, Lorca T, Castro A. PP2A-B55 Holoenzyme Regulation and Cancer. Biomolecules 2020; 10:biom10111586. [PMID: 33266510 PMCID: PMC7700614 DOI: 10.3390/biom10111586] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 01/05/2023] Open
Abstract
Protein phosphorylation is a post-translational modification essential for the control of the activity of most enzymes in the cell. This protein modification results from a fine-tuned balance between kinases and phosphatases. PP2A is one of the major serine/threonine phosphatases that is involved in the control of a myriad of different signaling cascades. This enzyme, often misregulated in cancer, is considered a tumor suppressor. In this review, we will focus on PP2A-B55, a particular holoenzyme of the family of the PP2A phosphatases whose specific role in cancer development and progression has only recently been highlighted. The discovery of the Greatwall (Gwl)/Arpp19-ENSA cascade, a new pathway specifically controlling PP2A-B55 activity, has been shown to be frequently altered in cancer. Herein, we will review the current knowledge about the mechanisms controlling the formation and the regulation of the activity of this phosphatase and its misregulation in cancer.
Collapse
|