We have analyzed proteins expressed in the glomerulus of normal human kidney by 2-DE and identification through MALDI-TOF MS and/or LC-MS/MS. Glomeruli were highly purified from kidney cortices with normal appearance obtained from patients under surgical nephrectomy due to renal tumors. The glomeruli were separated by 2-DE conducted with 25x20 cm 12.5 % separation gels coupled with IPG strips of pH range of 3-10, and silver-stained. From 2-DE gels of 5 subjects with no apparent pathologic manifestation, a synthetic gel image was produced by using PDQuest. Nearly 350 protein spots were so far identified, which were grouped into 18 lager categories on the basis of Gene Ontology terms. Although most of proteins identified include cell structural proteins, metabolic enzymes, and protein metabolism, significant number of proteins implicated in signal transduction (25), cell cycle and proliferation (10), and stress response (13) were also identified. Thus, our database might be useful for elucidating biological processes altered under different physiological or pathological conditions, although identified proteins were only a fraction of all the proteins expressed in the glomerulus. In order to improve proteomic approach for the glomerulus, we have undertaken analysis to specify proteins abundantly expressed in the glomerulus of normal kidney, and have already detected 204 proteins preferentially expressed in the glomeruli. A database of normal glomerular proteome are now being constructed by an XML-based editor (HUP-ML) designed for construction of proteome database. The database includes annotations such as protein name and synonyms, accession number of protein database, observed and theoretical pI and Mw, accession number of cDNA database, gene name, GO classifications, and other probable candidates or co-migrated proteins. The database will be submitted on a Web site for public access.
