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Wilson PG, Abdelmoti L, Gao T, Galperin E. The expression of congenital Shoc2 variants induces AKT-dependent crosstalk activation of the ERK1/2 pathway. Hum Mol Genet 2024; 33:1592-1604. [PMID: 38881369 PMCID: PMC11373329 DOI: 10.1093/hmg/ddae100] [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: 03/01/2024] [Revised: 04/11/2024] [Accepted: 06/10/2024] [Indexed: 06/18/2024] Open
Abstract
The Shoc2 scaffold protein is crucial in transmitting signals within the Epidermal Growth Factor Receptor (EGFR)-mediated Extracellular signal-Regulated Kinase (ERK1/2) pathway. While the significance of Shoc2 in this pathway is well-established, the precise mechanisms through which Shoc2 governs signal transmission remain to be fully elucidated. Hereditary variants in Shoc2 are responsible for Noonan Syndrome with Loose anagen Hair (NSLH). However, due to the absence of known enzymatic activity in Shoc2, directly assessing how these variants affect its function is challenging. ERK1/2 phosphorylation is used as a primary parameter of Shoc2 function, but the impact of Shoc2 mutants on the pathway activation is unclear. This study investigates how the NSLH-associated Shoc2 variants influence EGFR signals in the context of the ERK1/2 and AKT downstream signaling pathways. We show that when the ERK1/2 pathway is a primary signaling pathway activated downstream of EGFR, Shoc2 variants cannot upregulate ERK1/2 phosphorylation to the level of the WT Shoc2. Yet, when the AKT and ERK1/2 pathways were activated, in cells expressing Shoc2 variants, ERK1/2 phosphorylation was higher than in cells expressing WT Shoc2. In cells expressing the Shoc2 NSLH mutants, we found that the AKT signaling pathway triggers the PAK activation, followed by phosphorylation of Raf-1/MEK1/2 and activation of the ERK1/2 signaling axis. Hence, our studies reveal a previously unrecognized feedback regulation downstream of the EGFR and provide additional evidence for the role of Shoc2 as a "gatekeeper" in controlling the selection of downstream effectors within the EGFR signaling network.
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Affiliation(s)
- Patricia G Wilson
- Department of Molecular and Cellular Biochemistry, University of Kentucky, 741 S Limestone St, Lexington, KY 40536, United States
| | - Lina Abdelmoti
- Department of Molecular and Cellular Biochemistry, University of Kentucky, 741 S Limestone St, Lexington, KY 40536, United States
| | - Tianyan Gao
- Department of Molecular and Cellular Biochemistry, University of Kentucky, 741 S Limestone St, Lexington, KY 40536, United States
| | - Emilia Galperin
- Department of Molecular and Cellular Biochemistry, University of Kentucky, 741 S Limestone St, Lexington, KY 40536, United States
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Maity S, Huang Y, Kilgore MD, Thurmon AN, Vaasjo LO, Galazo MJ, Xu X, Cao J, Wang X, Ning B, Liu N, Fan J. Mapping dynamic molecular changes in hippocampal subregions after traumatic brain injury through spatial proteomics. Clin Proteomics 2024; 21:32. [PMID: 38735925 PMCID: PMC11089002 DOI: 10.1186/s12014-024-09485-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 04/24/2024] [Indexed: 05/14/2024] Open
Abstract
BACKGROUND Traumatic brain injury (TBI) often results in diverse molecular responses, challenging traditional proteomic studies that measure average changes at tissue levels and fail to capture the complexity and heterogeneity of the affected tissues. Spatial proteomics offers a solution by providing insights into sub-region-specific alterations within tissues. This study focuses on the hippocampal sub-regions, analyzing proteomic expression profiles in mice at the acute (1 day) and subacute (7 days) phases of post-TBI to understand subregion-specific vulnerabilities and long-term consequences. METHODS Three mice brains were collected from each group, including Sham, 1-day post-TBI and 7-day post-TBI. Hippocampal subregions were extracted using Laser Microdissection (LMD) and subsequently analyzed by label-free quantitative proteomics. RESULTS The spatial analysis reveals region-specific protein abundance changes, highlighting the elevation of FN1, LGALS3BP, HP, and MUG-1 in the stratum moleculare (SM), suggesting potential immune cell enrichment post-TBI. Notably, established markers of chronic traumatic encephalopathy, IGHM and B2M, exhibit specific upregulation in the dentate gyrus bottom (DG2) independent of direct mechanical injury. Metabolic pathway analysis identifies disturbances in glucose and lipid metabolism, coupled with activated cholesterol synthesis pathways enriched in SM at 7-Day post-TBI and subsequently in deeper DG1 and DG2 suggesting a role in neurogenesis and the onset of recovery. Coordinated activation of neuroglia and microtubule dynamics in DG2 suggest recovery mechanisms in less affected regions. Cluster analysis revealed spatial variations post-TBI, indicative of dysregulated neuronal plasticity and neurogenesis and further predisposition to neurological disorders. TBI-induced protein upregulation (MUG-1, PZP, GFAP, TJP, STAT-1, and CD44) across hippocampal sub-regions indicates shared molecular responses and links to neurological disorders. Spatial variations were demonstrated by proteins dysregulated in both or either of the time-points exclusively in each subregion (ELAVL2, CLIC1 in PL, CD44 and MUG-1 in SM, and SHOC2, LGALS3 in DG). CONCLUSIONS Utilizing advanced spatial proteomics techniques, the study unveils the dynamic molecular responses in distinct hippocampal subregions post-TBI. It uncovers region-specific vulnerabilities and dysregulated neuronal processes, and potential recovery-related pathways that contribute to our understanding of TBI's neurological consequences and provides valuable insights for biomarker discovery and therapeutic targets.
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Affiliation(s)
- Sudipa Maity
- Center for Cellular and Molecular Diagnostics, Tulane University School of Medicine, New Orleans, LA, USA
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Yuanyu Huang
- Center for Cellular and Molecular Diagnostics, Tulane University School of Medicine, New Orleans, LA, USA
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Mitchell D Kilgore
- Clinical Neuroscience Research Center, Department of Neurosurgery and Neurology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Abbigail N Thurmon
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, USA
- Tulane Brain Institute, New Orleans, LA, USA
| | | | - Maria J Galazo
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, USA
- Tulane Brain Institute, New Orleans, LA, USA
| | - Xiaojiang Xu
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA, USA
| | - Jing Cao
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaoying Wang
- Clinical Neuroscience Research Center, Department of Neurosurgery and Neurology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Bo Ning
- Center for Cellular and Molecular Diagnostics, Tulane University School of Medicine, New Orleans, LA, USA
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Ning Liu
- Clinical Neuroscience Research Center, Department of Neurosurgery and Neurology, Tulane University School of Medicine, New Orleans, LA, USA.
- Tulane University Translational Sciences Institute, New Orleans, LA, USA.
| | - Jia Fan
- Center for Cellular and Molecular Diagnostics, Tulane University School of Medicine, New Orleans, LA, USA.
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA.
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Wilson P, Abdelmoti L, Gao T, Galperin E. The expression of congenital Shoc2 variants induces AKT-dependent feedback activation of the ERK1/2 pathway. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.23.573219. [PMID: 38187642 PMCID: PMC10769455 DOI: 10.1101/2023.12.23.573219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
The Shoc2 scaffold protein is crucial in transmitting signals within the Epidermal Growth Factor Receptor (EGFR)-mediated Extracellular signal-regulated Kinase (ERK1/2) pathway. While the significance of Shoc2 in this pathway is well-established, the precise mechanisms through which Shoc2 governs signal transmission remain to be fully elucidated. Hereditary mutations in Shoc2 are responsible for Noonan Syndrome with Loose anagen Hair (NSLH). However, due to the absence of known enzymatic activity in Shoc2, directly assessing how these mutations affect its function is challenging. ERK1/2 phosphorylation is used as a primary parameter of Shoc2 function, but the impact of Shoc2 mutants on the pathway activation is unclear. This study investigates how the NSLH-associated Shoc2 variants influence EGFR signals in the context of the ERK1/2 and AKT downstream signaling pathways. We show that when the ERK1/2 pathway is a primary signaling pathway activated downstream of EGFR, Shoc2 variants cannot upregulate ERK1/2 phosphorylation to the level of the WT Shoc2. Yet, when the AKT and ERK1/2 pathways were activated, in cells expressing Shoc2 variants, ERK1/2 phosphorylation was higher than in cells expressing WT Shoc2. We found that, in cells expressing the Shoc2 NSLH mutants, the AKT signaling pathway triggers the PAK activation, followed by phosphorylation and Raf-1/MEK1/2 /ERK1/2 signaling axis activation. Hence, our studies reveal a previously unrecognized feedback regulation downstream of the EGFR and provide evidence for the Shoc2 role as a "gatekeeper" in controlling the selection of downstream effectors within the EGFR signaling network.
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