Post-translational Modification Regulating Protein-protein And Peptide-Macrocycle Interactions

Post-translational modifications are important for regulating protein-protein interactions within many cellular signaling pathways.It is associated with the pathogenesis of many diseases.Most protein-protein interactions are achieved in multivalent interaction pattern,which enables a strong and reversible interacion,triggering cascading signaling pathways or phase separation in vivo.Therefore,it is of great biological and medical significance to reveal the mechanism of post-translational modification regulated multivalent interaction.Rnd3 protein regulates lots of cellular processes and is associated with tumor development and metastasis.Its function is regulated by transcription,post-translation modification and localization within cells.There are a variety of post-translational modifications within the C-ternimal of Rnd3 protein,including phosphorylation,farnesylation and methyl esterification.These post-translation modifications bring different biological functions to Rnd3 protein.It has been documented that 14-3-3? is one of the proteins that interacts with Rnd3 protein.14-3-3? participates in many important signaling pathways in cells by binding to phosphorylated proteins.Here,Rnd3 peptides and 14-3-3? were used as models to elucidate the contributions of different modifications on multivalent interactions and the binding mechanism.Through the thermodynamic and kinetic studies,the contribution of phosphorylation at different sites on Rnd3 proteins bound with 14-3-3? were identified.A pattern of noncooperative(additive)model was proposed to elucidate the influence of multiphosphorylations on Rnd3 protein.Besides,a pattern of cooperative(induced-fit)mechanism was proposed to elucidate the combine influence of phosphorylation and farnesylation on Rnd3 protein.The model was also a general concept for describing the interactions between 14-3-3 and other substrates containing adjacent modifications.For the physiological function of Rnd3 protein,only by locating on cellular membrane can signaling pathways be transmitted.Here,a new type of protein,PDE?,is found to transport Rnd3 protein and PDE? protein only transports the farnesylated Rnd3.Once phosphorylation modification occurs near farnesylation on Rnd3,the PDE? protein loses the ability of transporting Rnd3.While 14-3-3? protein,which is weakly bound to farnesylated Rnd3,can well identify phosphorylated and farnesylated Rnd3 and stabilize Rnd3 in the cytoplasm.Therfore,a new transport mechanism for regulating the positioning of Rnd3 protein is proposed,which provides a new possibility for the research of Rnd3 functional regulation.In addition,abnormal modifications are associated with a lot of diseases or tumors.Biomarkers are promising candidates for cancer diagnosation and treatment.Here,posttranslational modification regulates the interaction between peptides and macrocycle has come to light.A variety of over-expressed enzyme biomarkers were detected through the regulating system by designing the logic gate system,which is of great significance for distinguishing different tumor systems.