title: [High glucose induces sumoylation of Smad4 via SUMO2/3 in glomerular mesangial cells].
abstract: OBJECTIVE
  To investigate the expression of SUMO2/3 and Smad4 in rat glomerular mesangial cells (GMCs) induced by high glucose, and the interaction between small ubiquitin related modifier (SUMO)2/3 and Smad4; and to explore the role and mechanism of sumoylation in regulating TGF-p signaling in diabetic nephropathy.
  
  
  METHODS
  Cultured rat GMCs were divided into five groups: normal glucose group (5. 6 mmol/L glucose), high glucose groups (10, 20 and 30 mmol/L glucose), and mannitol group (osmotic control). The expression of SUMO2/3, Smad4 and fibronectin (FN) was measured by Western blot and RT-PCR. The interaction and colocalization between SUMO2/3 and Smad4 were detected by Co-immunoprecipitation and immunofluorescence confocal laser microscopy.
  
  
  RESULTS
  Compared with controls, the expressions of SUMO2/3, Smad4 and FN in the cells in the high glucose groups increased (P < 0.05). The co-immunoprecipitation and immunofluorescence confocal laser scanning showed that Smad4 interacted and colocalized with SUMO2/3 and the sumolyation (SUMO2/3) of Smad4 was enhanced significantly in the high glucose groups compared with the control group (P < 0.05).
  
  
  CONCLUSIONS
  Sumolyation of Samd4 by SUMO2/3 may be involved in the regulation of TGF-beta signaling in diabetic nephropathy.
authors.forename: Xue-qin
authors.initials: XQ
authors.lastname: Zhou
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: Yong
authors.initials: Y
authors.lastname: Xu
authors.forename: Mao-jun
authors.initials: MJ
authors.lastname: Yang
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003470:Culture Media / Q000737:chemistry; D003928:Diabetic Nephropathies / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D005920:Glomerular Mesangium / Q000166:cytology; D005947:Glucose / Q000737:chemistry; D047468:Immunoprecipitation; D050527:Mesangial Cells / Q000378:metabolism*; D012333:RNA, Messenger; D051381:Rats; D015398:Signal Transduction; D051901:Smad4 Protein / Q000378:metabolism*; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism*; D058207:Sumoylation; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: D003470:Culture Media; D005353:Fibronectins; D012333:RNA, Messenger; C529669:SUMO2 protein, rat; C529670:SUMO3 protein, rat; D051901:Smad4 Protein; C490811:Smad4 protein, rat; D025841:Small Ubiquitin-Related Modifier Proteins; D016212:Transforming Growth Factor beta; D005947:Glucose