title: Palmitoylation regulates the intracellular trafficking and stability of c-Met.
abstract: c-Met is a receptor tyrosine kinase whose activity can promote both mitogenic and motogenic phenotypes involved in tissue development and cancer progression. Herein, we report the first evidence that c-Met is palmitoylated and that palmitoylation facilitates its trafficking and stability. Inhibition of palmitoylation reduced the expression of c-Met in multiple cancer cell lines post-transcriptionally. Using surface biotinylation, confocal microscopy, and metabolic labeling we determined that inhibition of palmitoylation reduces the stability of newly synthesized c-Met and causes accumulation at the Golgi. Acyl-biotin exchange and click chemistry-based palmitate labeling indicated the c-Met β-chain is palmitoylated, and site-directed mutagenesis revealed two likely cysteine palmitoylation sites. Moreover, by monitoring palmitoylation kinetics during the biosynthesis and trafficking of c-Met, we revealed that stable palmitoylation occurs in the endoplasmic reticulum prior to cleavage of the 170 kDa c-Met precursor to the mature 140 kDa form. Our data suggest palmitoylation is required for egress from the Golgi for transport to the plasma membrane. These findings introduce palmitoylation as a critical modification of c-Met, providing a novel therapeutic target for c-Met-driven cancers.
authors.affiliation: Department of Microbiology and Immunology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA.
authors.forename: David T
authors.initials: DT
authors.lastname: Coleman
authors.affiliation: Department of Microbiology and Immunology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA.
authors.forename: Alana L
authors.initials: AL
authors.lastname: Gray
authors.affiliation: Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC 25157, USA.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Kridel
authors.affiliation: Department of Microbiology and Immunology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA.
authors.forename: James A
authors.initials: JA
authors.lastname: Cardelli
mesh_terms: D045744:Cell Line, Tumor; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D054878:Lipoylation; D021381:Protein Transport; D019859:Proto-Oncogene Proteins c-met / Q000378:metabolism*; D055571:Secretory Pathway; D015398:Signal Transduction
chemical_list: C491743:MET protein, human; D019859:Proto-Oncogene Proteins c-met
keywords: c-Met; cancer; click chemistry; intracellular trafficking; palmitoylation