PXD059047-1

PXD059047 is an original dataset announced via ProteomeXchange.

Title	Balance between B55alpha and Greatwall expression levels predicts sensitivity to Greatwall inhibition in cancer cells
Description	The Greatwall kinase is a key cell cycle regulator responsible for the timely inactivation of PP2A-B55 phosphatases and consequential stabilisation of critical Cdk1-driven mitotic phosphorylation. Although Greatwall represents a potential oncogene and prospective therapeutic target, our understanding of cellular and molecular responses to chemical Greatwall inactivation remains limited. To address this, we introduce C-604, a highly selective Greatwall inhibitor, and characterise both immediate and long-term cellular responses to the chemical attenuation of Greatwall activity. We provide evidence suggesting that ENSA(S67), ARPP19(S62) and the Greatwall autophosphorylation site (T878) represent the only mitotic Greatwall substrates. Additionally, we demonstrate that Greatwall inhibition causes systemic destabilisation of mitotic phosphoproteome, premature mitotic exit and pleiotropic cellular pathologies. Importantly, we establish that cellular and molecular defects associated with low Greatwall activity arise from the untimely activation of PP2A complexes incorporating B55α but no other B55 isoforms, highlighting the unique role of PP2A-B55α phosphatases in shaping cellular responses to Greatwall-targeting compounds. Additionally, we show that sensitivity to Greatwall inhibition varies in different cell line models and that dependency on Greatwall activity reflects the balance between Greatwall and B55α expression levels. Our findings highlight Greatwall dependency as a cell-specific vulnerability and propose Greatwall and B55α expression levels as predictive biomarkers of cellular responses to Greatwall-targeted therapeutics.
HostingRepository	PRIDE
AnnounceDate	2025-07-21
AnnouncementXML	Submission_2025-07-21_05:19:15.365.xml
DigitalObjectIdentifier	https://dx.doi.org/10.6019/PXD059047
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Supported dataset by repository
PrimarySubmitter	Vinothini Rajeeve
SpeciesList	scientific name: Homo sapiens (Human); NCBI TaxID: 9606;
ModificationList	phosphorylated residue; monohydroxylated residue; iodoacetamide derivatized residue
Instrument	Q Exactive

Revision	Datetime	Status	ChangeLog Entry
0	2024-12-19 06:55:04	ID requested
⏵ 1	2025-07-21 05:19:15	announced

10.6019/PXD059047;

submitter keyword: Greatwall Kinase, phosphoproteome, mitosis, PP2A, cell cycle, B55alpha

Professor Pedro Cutillas
contact affiliation	Mass Spectrometry Facility Barts Cancer Institute Queen Mary, University of London John Vane Science Centre, Charterhouse Square, London EC1M 6BQ
contact email	p.cutillas@qmul.ac.uk
lab head
Vinothini Rajeeve
contact affiliation	Centre for Haemato Oncology
contact email	v.rajeeve@qmul.ac.uk
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD059047
     1. Label: PRIDE project
     2. Name: Balance between B55alpha and Greatwall expression levels predicts sensitivity to Greatwall inhibition in cancer cells