Dataset Information

Flotillin-2 regulates EGFR activation, degradation, and cancer growth

ABSTRACT: Epidermal growth factor receptor (EGFR) signaling is frequently dysregulated in a variety of cancers. The ubiquitin ligase Cbl regulates degradation of activated EGFR through ubiquitination and acts as an adaptor to recruit proteins required for trafficking. We used Stable Isotope Labeling with Amino Acids in Cell Culture (SILAC) mass spectrometry (MS) to compare Cbl complexes in the absence and presence of EGF stimulation. We identified over a hundred novel Cbl interactors, and a secondary siRNA screen found that knockdown of Flotillin-2 (FLOT2) led to increased phosphorylation and degradation of EGFR upon EGF stimulation in HeLa cells. In H441 cells, FLOT2 knockdown increased EGF-stimulated EGFR phosphorylation, ubiquitination, and downstream signaling, reversible by the EGFR inhibitor erlotinib. CRISPR knockout of FLOT2 in HeLa cells confirmed EGFR downregulation, increased signaling, and increased dimerization and trafficking to the early endosome. FLOT2 interacts with both Cbl and EGFR. Downregulation of EGFR upon FLOT2 loss is Cbl-dependent, as co-knockdown of Cbl and Cbl-b restored EGFR levels. Stable overexpression of FLOT2 in HeLa cells decreased EGF-stimulated EGFR phosphorylation and ubiquitination. Overexpression of wild type (WT) FLOT2, but not the soluble G2A FLOT2 mutant, inhibited EGFR phosphorylation upon EGF stimulation in HEK293T cells. FLOT2 loss induces EGFR-dependent proliferation and anchorage-independent cell growth. Lastly, FLOT2 knockout increases tumor formation and tumor volume in nude mice and NSG mice, respectively. These data demonstrate that FLOT2 negatively regulates EGFR activation and dimerization, as well as its subsequent ubiquitination, endosomal trafficking, and degradation. FLOT2 negatively regulates proliferation in vitro and in vivo.

INSTRUMENT(S): LTQ Orbitrap

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Epithelial Cell

DISEASE(S): Disease Free

SUBMITTER: Xu Zhang

LAB HEAD: Stanley Lipkowitz

PROVIDER: PXD031988 | Pride | 2023-03-11

REPOSITORIES: Pride

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Dataset's files

Source:

			Action	DRS
	CBL_IP_3s_Dec_F1.raw	Raw
	CBL_IP_3s_Dec_F10_150107160806.raw	Raw
	CBL_IP_3s_Dec_F11_150107182958.raw	Raw
	CBL_IP_3s_Dec_F12_150107205235.raw	Raw
	CBL_IP_3s_Dec_F13_150107231453.raw	Raw

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Publications

Flotillin-2 regulates epidermal growth factor receptor activation, degradation by Cbl-mediated ubiquitination, and cancer growth.

Wisniewski David J DJ Liyasova Mariya S MS Korrapati Soumya S Zhang Xu X Ratnayake Shashikala S Chen Qingrong Q Gilbert Samuel F SF Catalano Alexis A Voeller Donna D Meerzaman Daoud D Guha Udayan U Porat-Shliom Natalie N Annunziata Christina M CM Lipkowitz Stanley S

The Journal of biological chemistry 20221205 1

Epidermal growth factor receptor (EGFR) signaling is frequently dysregulated in various cancers. The ubiquitin ligase Casitas B-lineage lymphoma proto-oncogene (Cbl) regulates degradation of activated EGFR through ubiquitination and acts as an adaptor to recruit proteins required for trafficking. Here, we used stable isotope labeling with amino acids in cell culture mass spectrometry to compare Cbl complexes with or without epidermal growth factor (EGF) stimulation. We identified over a hundred ...[more]

PMID: 36470425

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Project description:Cysteine is a rare and conserved amino acid involved in most cellular functions. The thiol group of cysteine can be subjected to diverse oxidative modifications that regulate most physio-pathological states. Here, a Cysteine-specific Phosphonate Adaptable Tag (CysPAT) was synthesized to selectively label cysteine-containing peptides (Cys peptides) followed by enrichment with titanium dioxide (TiO2) and mass spectrometric analysis. The CysPAT strategy was developed using a synthetic peptide, a standard protein and subsequently the strategy was applied to Hela cells lysate, achieving high specificity and enrichment efficiency. In particular,From 500µg of Hela cell lysate, the method led to the identification of 9229 unique Cys peptides starting from 500µg of Hela cell lysate . the CysPAT labelled Cys peptides showed increased hydrophobicity. Finally, the method was further developed to simultaneously enrich Cys peptides and phosphorylated peptidesThe method was further developed to simultaneously enrich Cys peptides and phosphorylated peptides from SILAC labelled Hela cells subjected to 5 min epidermal growth factor (EGF) stimulation. In total, of 22972 unique reversibly modified Cys peptides (3886 proteins) and 18549 unique phosphopeptides (2257 proteins) were simultaneously identified by Orbitrap Fusion. Significant regulation was observed in both phosphorylation and reversible Cys modification of proteins interacted with EGF receptor (EGFR)-binding proteins and proteins involved in EGFR signaling pathway. EGF stimulation can activate the phosphorylation of EGFR and downstream signaling molecules, such as mitogen-activated protein kinases (MAPK1 and MAPK3), meanwhile, it also leads to the activation of multiple protein tyrosine phosphatases (PTPs) by reduction of the catalytic Cys site in the conserved putative phosphatase HC(X)5R motif, Llater the activated PTPs would dephosphorylate and inactivate the molecules activated by EGF stimulation. Overall, the CysPAT strategy is a promising tool for studying redox proteomics and the simultaneous enrichment strategy offers an excellent solution for characterization of cross-talk between phosphorylation and redox induced cysteine modifications.