title: Localization of discoidin domain receptors in rat kidney.
abstract: OBJECTIVE
  The discoidin domain receptors (DDRs) DDR1 and DDR2 are cardinal members of a receptor tyrosine kinase subfamily, activated by collagens. They are candidate effectors in tissue injury and fibrosis. We investigated the DDR expression in normal and remnant rat kidneys.
  
  
  METHODS
  The DDR expression in kidney and other tissues was examined by indirect immunofluorescence, immunoblotting, and ribonuclease protection assays. The expression patterns in remnant and control kidneys were compared at 2-, 4-, and 8-week time points, following induction of injury.
  
  
  RESULTS
  DDR1 is expressed in basolateral membranes of select nephron segments, from the connecting tubule to the renal papilla. DDR2 is expressed in apical membranes of select nephron segments, from the loop of Henle to the macula densa. The DDR1 protein expression is upregulated within the glomeruli of remnant kidneys. The distribution of DDR2 in remnant kidneys is similar to that in controls. The DDR mRNA levels in remnant and control kidneys were not significantly different, at any time point.
  
  
  CONCLUSIONS
  The DDR1 localization in the rat kidney is consistent with roles in cell-matrix interactions. Upregulation within glomeruli of remnant kidneys suggests the possibility of additional roles in kidney injury. The DDR2 localization in adult rat kidneys is inconsistent with roles in cell-matrix interactions.
authors.affiliation: Division of Renal Diseases and Hypertension, Department of Medicine, University of Minnesota, Minneapolis, Minn., USA.
authors.forename: Rutha
authors.initials: R
authors.lastname: Lee
authors.forename: Keith E
authors.initials: KE
authors.lastname: Eidman
authors.forename: Stefan M
authors.initials: SM
authors.lastname: Kren
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Hostetter
authors.forename: Yoav
authors.initials: Y
authors.lastname: Segal
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000737:chemistry; D003094:Collagen; D000070818:Discoidin Domain Receptors; D004195:Disease Models, Animal; D004848:Epithelium / Q000737:chemistry; D007668:Kidney / Q000737:chemistry* / Q000378:metabolism / Q000601:surgery; D008297:Male; D008970:Molecular Weight; D009399:Nephrons / Q000737:chemistry; D010455:Peptides / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D051381:Rats; D017207:Rats, Sprague-Dawley; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D011975:Receptors, Mitogen / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*
chemical_list: D010455:Peptides; D011975:Receptors, Mitogen; D003094:Collagen; D000070818:Discoidin Domain Receptors; D020794:Receptor Protein-Tyrosine Kinases