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Palmieri M, Catimel B, Mouradov D, Sakthianandeswaren A, Kapp E, Ang CS, Williamson NA, Nowell CJ, Christie M, Desai J, Gibbs P, Burgess AW, Sieber OM. PI3K-alpha translocation mediates nuclear PtdIns(3,4,5)P 3 effector signaling in colorectal cancer. Mol Cell Proteomics 2023; 22:100529. [PMID: 36931626 PMCID: PMC10130476 DOI: 10.1016/j.mcpro.2023.100529] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 03/05/2023] [Accepted: 03/13/2023] [Indexed: 03/17/2023] Open
Abstract
The canonical view of phosphatidylinositol 3-kinase alpha (PI3Kα) signaling describes PtdIns(3,4,5)P3 generation and activation of downstream effectors at the plasma membrane or at microtubule-bound endosomes. Here, we show that colorectal cancer (CRC) cell lines exhibit a diverse plasma membrane-nuclear distribution of PI3Kα, controlling corresponding levels of subcellular PtdIns(3,4,5)P3 pools. PI3Kα nuclear translocation was mediated by the importin β-dependent nuclear import pathway. By PtdIns(3,4,5)P3 affinity capture mass spectrometry done in the presence of SDS on CRC cell lines with PI3Kα nuclear localization, we identified 867 potential nuclear PtdIns(3,4,5)P3 effector proteins. Nuclear PtdIns(3,4,5)P3 interactome proteins were characterized by non-canonical PtdIns(3,4,5)P3 binding domains and showed overrepresentation for nuclear membrane, nucleolus and nuclear speckles. The nuclear PtdIns(3,4,5)P3 interactome was enriched for proteins related to RNA metabolism, with splicing reporter assays and SC-35 foci staining suggesting a role of EGF-stimulated nuclear PI3Kα signaling in modulating pre-mRNA splicing. In patient tumors, nuclear p110α staining was associated with lower T stage and mucinous histology. These results indicate that PI3Kα translocation mediates nuclear PtdIns(3,4,5)P3 effector signaling in human CRC, modulating signaling responses.
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Affiliation(s)
- Michelle Palmieri
- Personalised Oncology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Bruno Catimel
- Personalised Oncology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Dmitri Mouradov
- Personalised Oncology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Anuratha Sakthianandeswaren
- Personalised Oncology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia
| | - Eugene Kapp
- Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia; Advanced Technology and Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia
| | - Ching-Seng Ang
- Bio21 Mass Spectrometry and Proteomics Facility, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Nicholas A Williamson
- Bio21 Mass Spectrometry and Proteomics Facility, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Cameron J Nowell
- Monash Institute for Pharmaceutical Science, Parkville, Victoria, 3052, Australia
| | - Michael Christie
- Personalised Oncology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia; Department of Pathology, Royal Melbourne Hospital, Parkville, Victoria, 3050, Australia
| | - Jayesh Desai
- Division of Cancer Medicine, Peter MacCallum Cancer Centre, Melbourne, Victoria, 3000, Australia; Department of Medical Oncology, Royal Melbourne Hospital, Parkville, Victoria, 3050, Australia
| | - Peter Gibbs
- Personalised Oncology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia; Department of Medical Oncology, Western Health, Footscray, Victoria, 3011, Australia
| | - Antony W Burgess
- Personalised Oncology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia; Department of Surgery, The University of Melbourne, Parkville, Victoria, 3050, Australia
| | - Oliver M Sieber
- Personalised Oncology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Victoria, 3052, Australia; Department of Surgery, The University of Melbourne, Parkville, Victoria, 3050, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, 3800, Australia.
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