Function Analysis Of The Arabidopsis SNARE Protein AtSed5 In Vesicle Transprotation

The material communication between the various components of the endomembrane system is mediated by vesicle transportation.Vesicle transportation consists of four steps,including budding,movement,tethering,and fusion.During the transportation,many factors are involved,for example Coat,SM,Tether,SNARE and Rab.Among these factors,SNARE proteins play an essential role in fusion.In the cell,based on the location SNARE proteins can be grouped into two categories:vesicle SNAREs(v-SNAREs),which are localized on transport vesicles,and target SNAREs(t-SNAREs).which are localized on the target membrane.During the fusion,the transport vesicles dock at target membrane surface,and three t-SNAREs on the target membrane and one v-SNARE on the transport vesicle form the SNARE complex,which promotes vesicle membrane and target membrane fusion.Then,vesicle fusions with the target membrane to form hole,through which vesicle releases the material.Then the fusion is completed.t-SNARE is divided into three categories,the most important of which is the syntaxin protein.The syntaxin protein plays an importent role for the formation and the stability of the SNARE complex.In yeast cells Sed5 is a syntaxin protein localizing in the Golgi apparatus which interacts with one SM protain SL1 to regulate Golgi SNARE complex stability.In Arabidopsis,the syntaxin protein localizing in the Golgi apparatus is still unkown.Through bioinformatic analysis,the syntaxin protein maybe AtSed5.AtSed5 of Arabidopsis maybe regulate the stability of the SNARE complex on the Golgi apparatus through interacting with SM protain AtSL1.In Arabidopsis.the candidates of AtSed5 are AtSYP331 and AtSYP332.In this study we make phenotype analysis of AtSYP331 and AtSYP332 RNAi homo lines and western blot and silver staining analysis of overexpressing transgenic plant of AtSYP331 and AtSYP332.At the same time we make two-hybrid experiment and transient expression about related gene yeast.Results indicate that,both AtSYP331 and AtSYP332 locate on Golgi apparatus.In yeast cell,both AtSYP331 and AtSYP332 are interactive with AtSL1.However,in plant cell only AtSYP332 can interact with AtSL1,which doesn't occur with AtSYP331.Furthermore,AtSYP331 and AtSYP332 exerts their bio-function during the process of seed germination and plant growth,but the molecular mechanism is unclear.