Study On The Sequence Of Munc13?Munc18 And Syntaxin In Regulating Vesicle Secretion

The nervous system is a functional module that is responsible for receiving and processing information of the human body.It transforms different kinds of information into electrochemical signals.With the participation of tens of thousands of nerve cells,it completes the transmission of information and maintains the normal operation of the body.Once the nerve activity is abnormal,it will lead to Alzheimer's disease,epilepsy and other neurological diseases,to the human and social burden.Interpreting the transmission of neural signals is one of the major topics in neuroscience.Nerve signaling is tightly regulated by a variety of proteins within vesicles.At present,studies have found that SNARE complex is the core component of vesicle fusion,which is conservative in many species.Almost all membrane fusion processes require the participation of SNARE complex.SNARE-mediated vesicle fusion requires the involvement of many proteins,and the order in which different proteins participate is still not fully understood.Here syntaxin,Munc13,Munc18 three proteins were studied for analyzing its function and role in vesicle fusion order.Through the generation of cultured mouse cerebral cortex neurons,preparation and infection of the target gene containing lentivirus in the nerve cells,we detect the release of the vesicles with patch clamp technique.We found that Munc13 NF,Munc18 KKEE and Syx RI mutations all affected the normal release of vesicles.Munc13 can catalyze the formation of an open conformation of Syntaxin.Mutations in NF residues of Munc13 affect the conformation transformation of Syx,and we restored the release level of vesicles by overexpressing the Syx LE mutant,indicating that Munc13 has no effect on the vesicle secretion process after the formation of Syx into an open conformation,that is,Munc13 plays a catalytic role before the formation of Syx into an open conformation.Studies have shown that Munc18 KKEE mutations affect the vesicle initiation process.According to the experimental results,Munc18 KKEE residue mutation can hinder the vesicle release process.We restored the vesicle release level by overexpressing the Syx LE mutant.This indicates that Munc18 primes Syx before it forms an open conformation.TheSyx RI mutation hinders the interaction between Syx and Munc13.According to the experimental results,the Syx RI mutation can affect vesicle release,and the over-expression of Munc18 P335 A mutant can restore vesicle release,indicating that after the completion of the activation of Munc18 P335 A mutant on vesicles,Munc13 has no influence on the vesicle secretion process,that is,Munc13 plays a role before Munc18 in the vesicle release process.In summary,Munc13,Munc18 and Syx are required to play a role in the process of vesicle release.This experiment provides some reference for explaining the regulation mechanism of transmitter release.