Abstract
The aim of this study is to identify the functional protein components of rice Golgi complex. In the present study, we attempted to purify cis-Golgi membranes from rice cells expressing GFP-AtSYP31 fusion protein which is known to localize in the cis-Golgi compartment. GFP-AtSYP31 labeled Golgi membranes were succeeded to highly purify by floating membranes in a sucrose density gradient. The specific GFP fluorescence intensity of final cis-Golgi membrane preparation was approximately 20-fold compared with that of crude microsomal membranes. The cis-Golgi membrane proteins were subjected to SDS-PAGE, followed by LC-MS/MS analysis. In addition to the Golgi localized protein such as root hair defective 3, COP-I and -II coatmer proteins, and small GTPase YPT3, Bip, calreticulin and Hsp90 those are well-known as ER membrane proteins were also identified. These results may indicate that there exist a similarity and/or continuance between cis-Golgi and ER membranes.
