NMR and biochemical characterization of the interaction between FGFR1 juxtamembrane domain and phospholipids

Fibroblast growth factor receptors (FGFRs) play an important role in the regulation of cell proliferation, migration and differentiation, while the juxtamembrane domain (JMD) of FGFRs is the key in mediating these transmembrane signal transduction processes. Here, we expressed and purified the JMD (398K-470R) of FGFR1 with the presence of transmembrane domain (377I-397Y). The results from nuclear magnetic resonance (NMR) chemical shift analysis demonstrate that the main structure of JMD is disordered. Yet, the N-terminus of JMD was observed to form a short α-helix upon introducing negatively charged lipid 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS) into its membrane mimic bicelles. Moreover, the N-terminus of JMD interacts with FRS2α, which is a substrate 2α of FGFR. Hence, we propose a model that FGFR1-JMD may interact with FRS2α and negatively charged lipids competitively. Our study provides a new understanding on the role of the JMD of FGFRs.