N-myristoylation regulates insulin-induced phosphorylation and ubiquitination of Caveolin-2 for insulin signaling

• Published in: Biochemical and biophysical research communications 2020-11, Vol.532 (4), p.535-540
• Main Authors: Kwon, Hayeong, Choi, Moonjeong, Ahn, Yujin, Pak, Yunbae
• Format: Article
• Language: English
• Subjects: Animals; Caveolin 2 - chemistry; Caveolin 2 - metabolism; Caveolin-2; Cell Line; Humans; Insulin - physiology; Insulin receptor; Lipoylation; Membrane Microdomains - metabolism; Myristic Acid - metabolism; N-myristoylation; Phosphorylation; Protein-tyrosine phosphatase 1B; Rats; Receptor, Insulin - metabolism; Signal Transduction; Tyrosine - metabolism; Ubiquitination
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2020.08.072

N-myristoylation is a ubiquitous protein lipidation in eukaryotes, but regulatory roles for myristoylation on proteins still remain to be explored. Here, we show that N-myristoylation of Caveolin-2 (Cav-2) controls insulin signaling. Alternative translation initiation (ATI)-yielded truncated form of non-N-myristoylable Cav-2β and various conditional Cav-2 mutants were compared to full-length form of N-myristoylable Cav-2α. Insulin induced insulin receptor (IR) tyrosine kinase-catalyzed Tyr-19 phosphorylation of N-myristoylable M14A Cav-2 and triggered activation of IR signaling cascade. In contrast, insulin induced ubiquitination of non-N-myristoylable M1A and G2A Cav-2 to facilitate protein-tyrosine phosphatase 1B interaction with IR which desensitized IR signaling through internalization. Metabolic labeling and click chemistry showed palmitoylation of M14A but not M1A and G2A Cav-2. Insulin did not induce phosphorylation of M1A and G2A Cav-2 and Cav-2β. Like Cav-2α, G2A Cav-2 and Cav-2β formed large homo-oligomers localized in lipid rafts. These findings show Cav-2 N-myristoylation plays a crucial role to coordinate its phosphorylation, palmitoylation, and ubiquitination to control insulin signaling. •N-myristoylation (MYR) of Cav-2 controls insulin receptor (IR) signaling.•MYR is required for phosphorylation of Cav-2 by IR to activate insulin signaling.•MYR-dependent palmitoylation facilitates the Cav-2 phosphorylation.•MYR prevents ubiquitination and internalization of Cav-2 to block IR desensitization.•MYR is dispensable for Cav-2 oligomerization and localization in lipid rafts.