SMAD2 and diabetes mellitus: For example, glomerular expression of fibronectin, collagen IV and TGF-β1,smad2/3, and ERK1/2 signaling, urinary TGF-β1 and renal glucose transporter (GLUT 1) have been found to be increased after 6–8 weeks of diabetes, and these parameters are improved with various interventions of 2–3 months duration (D'Agord Schaan et al. 2001; Chen et al. 2011; Quilley et al. 2011).