1
|
Molyneaux K, Laggner C, Brady‐Kalnay SM. A novel binding pocket in the D2 domain of protein tyrosine phosphatase mu (PTPmu) guides AI screen to identify small molecules that modulate tumour cell adhesion, growth and migration. J Cell Mol Med 2023; 27:3553-3564. [PMID: 37860940 PMCID: PMC10660673 DOI: 10.1111/jcmm.17973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 08/25/2023] [Accepted: 09/16/2023] [Indexed: 10/21/2023] Open
Abstract
Approximately 40% of people will get cancer in their lifetime in the US, and 20% are predicted to die from the condition when it is invasive and metastatic. Targeted screening for drugs that interact with proteins that drive cancer cell growth and migration can lead to new therapies. We screened molecular libraries with the AtomNet® AI-based drug design tool to identify compounds predicted to interact with the cytoplasmic domain of protein tyrosine phosphatase mu. Protein tyrosine phosphatase mu (PTPmu) is proteolytically downregulated in cancers such as glioblastoma generating fragments that stimulate cell survival and migration. Aberrant nuclear localization of PTPmu intracellular fragments drives cancer progression, so we targeted a predicted drug-binding site between the two cytoplasmic phosphatase domains we termed a D2 binding pocket. The function of the D2 domain is controversial with various proposed regulatory functions, making the D2 domain an attractive target for the development of allosteric drugs. Seventy-five of the best-scoring and chemically diverse computational hits predicted to interact with the D2 binding pocket were screened for effects on tumour cell motility and growth in 3D culture as well as in a direct assay for PTPmu-dependent adhesion. We identified two high-priority hits that inhibited the migration and glioma cell sphere formation of multiple glioma tumour cell lines as well as aggregation. We also identified one activator of PTPmu-dependent aggregation, which was able to stimulate cell migration. We propose that the PTPmu D2 binding pocket represents a novel regulatory site and that inhibitors targeting this region may have therapeutic potential for treating cancer.
Collapse
Affiliation(s)
- Kathleen Molyneaux
- Department of Molecular Biology & MicrobiologyCase Western Reserve UniversityClevelandOhioUSA
| | | | - Susann M. Brady‐Kalnay
- Department of Molecular Biology & MicrobiologyCase Western Reserve UniversityClevelandOhioUSA
| |
Collapse
|
2
|
Fearnley GW, Young KA, Edgar JR, Antrobus R, Hay IM, Liang WC, Martinez-Martin N, Lin W, Deane JE, Sharpe HJ. The homophilic receptor PTPRK selectively dephosphorylates multiple junctional regulators to promote cell-cell adhesion. eLife 2019; 8:44597. [PMID: 30924770 PMCID: PMC6440744 DOI: 10.7554/elife.44597] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 03/23/2019] [Indexed: 12/20/2022] Open
Abstract
Cell-cell communication in multicellular organisms depends on the dynamic and reversible phosphorylation of protein tyrosine residues. The receptor-linked protein tyrosine phosphatases (RPTPs) receive cues from the extracellular environment and are well placed to influence cell signaling. However, the direct events downstream of these receptors have been challenging to resolve. We report here that the homophilic receptor PTPRK is stabilized at cell-cell contacts in epithelial cells. By combining interaction studies, quantitative tyrosine phosphoproteomics, proximity labeling and dephosphorylation assays we identify high confidence PTPRK substrates. PTPRK directly and selectively dephosphorylates at least five substrates, including Afadin, PARD3 and δ-catenin family members, which are all important cell-cell adhesion regulators. In line with this, loss of PTPRK phosphatase activity leads to disrupted cell junctions and increased invasive characteristics. Thus, identifying PTPRK substrates provides insight into its downstream signaling and a potential molecular explanation for its proposed tumor suppressor function.
Collapse
Affiliation(s)
- Gareth W Fearnley
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Katherine A Young
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - James R Edgar
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom.,Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Robin Antrobus
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Iain M Hay
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Wei-Ching Liang
- Antibody Engineering Department, Genentech, South San Francisco, United States
| | - Nadia Martinez-Martin
- Microchemistry, Proteomics and Lipidomics Department, Genentech, South San Francisco, United States
| | - WeiYu Lin
- Antibody Engineering Department, Genentech, South San Francisco, United States
| | - Janet E Deane
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Hayley J Sharpe
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| |
Collapse
|