Function First Exploration Of Arabidopsis V-SNARE In Vesicle Trafficking Between ER And Golgi

In high plant,during the maturation of the seeds,massive seed storage proteins are synthesized and storage to provide source of N and C during germination and early development.Seed storage proteins are synthetized as large precursors on the rough endoplasmic reticulum(ER),and then are transported to vacuole where they are processed into mature forms Storage protein transport depend on vesicular transport.There are five steps of vesicular transport including budding,transport,tethering anchoring and fusion.SNARE proteins play an important role on membrane fusion,because the SNARE complexes which is formed by different SNAREs from target membrane and vesicles,respectively,mediate membrane fusion.In yeast cells,Sec22p functions in a complexcontaining the ER-localized SNARE Ufelp,Sltlp and Sec22p,mediating fusion of vesicles with the ER in retrograde transport.There is a functional redundancy between Ykt6p and Sec22p in yeast cells.The Sec22p orthologs in Arabidopsis is AtSec22,but the function is still unclear.Whether AtYkt61,the Ykt6p orthologs in Arabidopsis,is involved in vesicular transport between endoplasmic reticulum and Golgi apparatus is also unclear.In this study we isolated A.thaliana mip mutants and observed phenotypes.We also performed biochemistry and molecular biology analyses.Our results indicate that AtYkt61 may be the v-SNARE which is involved in Golgi to ER retrograde transport..AtSec22 may play an important role in anterograde transport from ER to Golgi.