Prenylated PALM2 Promotes the Migration of Esophageal Squamous Cell Carcinoma Cells Through Activating Ezrin

• Published in: Molecular & cellular proteomics Vol. 22; no. 8; p. 100593
• Main Authors: Deng, Dan-Xia, Li, Cheng-Yu, Zheng, Zhen-Yuan, Wen, Bing, Liao, Lian-Di, Zhang, Xiao-Jun, Li, En-Min, Xu, Li-Yan
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.08.2023; American Society for Biochemistry and Molecular Biology
• Subjects: cell migration; esophageal squamous cell carcinoma; ezrin; PALM2; prenylation; ERM; GPI; HEK 293T; PALM2; HRP; PALM3; PTM; ezrin; PALMD; PALM; cell migration; prenylation; KEGG; RCE1; esophageal squamous cell carcinoma; ICMT; FTase; GGTase-type I; GO; DAPI; NEB; ESCC; PEI; GGTase-type II; PIP2
• ISSN: 1535-9476; 1535-9484
• DOI: 10.1016/j.mcpro.2023.100593

Proteins containing a CAAX motif at the C-terminus undergo prenylation for localization and activity and include a series of key regulatory proteins, such as RAS superfamily members, heterotrimeric G proteins, nuclear lamina protein, and several protein kinases and phosphatases. However, studies of prenylated proteins in esophageal cancer are limited. Here, through research on large-scale proteomic data of esophageal cancer in our laboratory, we found that paralemmin-2 (PALM2), a potential prenylated protein, was upregulated and associated with poor prognosis in patients. Low-throughput verification showed that the expression of PALM2 in esophageal cancer tissues was higher than that in their paired normal esophageal epithelial tissues, and it was generally expressed in the membrane and cytoplasm of esophageal cancer cells. PALM2 interacted with the two subunits of farnesyl transferase (FTase), FNTA and FNTB. Either the addition of an FTase inhibitor or mutation in the CAAX motif of PALM2 (PALM2C408S) impaired its membranous localization and reduced the membrane location of PALM2, indicating PALM2 was prenylated by FTase. Overexpression of PALM2 enhanced the migration of esophageal squamous cell carcinoma cells, whereas PALM2C408S lost this ability. Mechanistically, PALM2 interacted with the N-terminal FERM domain of ezrin of the ezrin/radixin/moesin (ERM) family. Mutagenesis indicated that lysine residues K253/K254/K262/K263 in ezrin’s FERM domain and C408 in PALM2’s CAAX motif were important for PALM2/ezrin interaction and ezrin activation. Knockout of ezrin prevented enhanced cancer cell migration by PALM2 overexpression. PALM2, depending on its prenylation, increased both ezrin membrane localization and phosphorylation of ezrin at Y146. In summary, prenylated PALM2 enhances the migration of cancer cells by activating ezrin. [Display omitted] •Upregulated PALM2 is associated with poor prognosis of esophageal cancer patients.•PALM2 can be prenylated at the CAAX motif of the C-terminus.•Prenylated PALM2 activates ezrin to promote the migration of esophageal cancer cells. Prenylation is a conservative lipid modification that regulates membrane-protein and protein-protein interactions in cell signaling. Our studies show that the prenylation of PALM2 is catalyzed by FTase, and prenylated PALM2 promotes cell migration of ESCC through activating ezrin by increasing ezrin’s membranous distribution and Y146 phosphorylation. Up-regulated PALM2 is associated with a shorter survival time of esophageal cancer patients and is an independent prognostic factor. This indicates that PALM2 can be a potential target for esophageal cancer prevention and therapy.