title: Differential expression of cytosolic proteins in the rat kidney cortex and medulla: preliminary proteomics.
abstract: The rodent kidney is a target of many xenobiotics and is typified by regionally specific structure and function. This renders distinct regions of the kidney differentially susceptible to toxic exposure and effect. To characterize these differences at the proteome level, protein patterns from male rat kidney cortex and medulla cytosols were examined by two-dimensional electrophoresis (2-DE) and image analysis and prominent proteins identified immunologically or by matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) and electrospray/ionization-tandem mass spectrometry (ESI-MS/MS) sequence tag identification. An average of 727 protein spots were resolved and matched to the cortex cytosol reference pattern, and 716 in the medulla. Of this total, 127 proteins were found to differ in abundance (86 higher in cortex; 41 higher in medulla) (P < 0.001). Of those proteins that were detectable in both cortex and medulla, the abundance of 97 differed significantly while 30 proteins were found to be unique to one region or the other (26 in cortex, 4 in medulla). Twenty protein spots were identified and their regional differences are discussed. These results both confirm and expand our understanding of the molecular heterogeneity characterizing structurally and functionally distinct regions of the kidney and serve as a useful foundation for future nephrotoxicologic studies.
authors.affiliation: Department of Biology, Indiana University-Purdue University, Columbus 47203, USA. fwitzman@iupui.edu
authors.forename: F A
authors.initials: FA
authors.lastname: Witzmann
authors.forename: C D
authors.initials: CD
authors.lastname: Fultz
authors.forename: R A
authors.initials: RA
authors.lastname: Grant
authors.forename: L S
authors.initials: LS
authors.lastname: Wright
authors.forename: S E
authors.initials: SE
authors.lastname: Kornguth
authors.forename: F L
authors.initials: FL
authors.lastname: Siegel
mesh_terms: D000510:Alpha-Globulins / Q000032:analysis; D000818:Animals; D001124:Argininosuccinate Synthase / Q000032:analysis; D064026:Calbindins; D019703:Calcineurin / Q000032:analysis; D003600:Cytosol / Q000737:chemistry*; D015180:Electrophoresis, Gel, Two-Dimensional; D005982:Glutathione Transferase / Q000032:analysis; D007672:Kidney Cortex / Q000648:ultrastructure*; D007679:Kidney Medulla / Q000737:chemistry*; D008297:Male; D011506:Proteins / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D064030:S100 Calcium Binding Protein G / Q000032:analysis; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014174:Transketolase / Q000032:analysis
chemical_list: D000510:Alpha-Globulins; D064026:Calbindins; D011506:Proteins; D064030:S100 Calcium Binding Protein G; C013803:alpha 2u globulin; D014174:Transketolase; D005982:Glutathione Transferase; D019703:Calcineurin; D001124:Argininosuccinate Synthase