title: Insulin-regulated aminopeptidase in adipocyte is Cys-specific and affected by obesity.
abstract: Insulin-regulated aminopeptidase (IRAP, EC 3.4.11.3) in adipocytes is well known to traffic between high (HDM) and low (LDM) density microsomal fractions toward the plasma membrane (MF) under stimulation by insulin. However, its catalytic preference for aminoacyl substrates with N-terminal Leu or Cys is controversial. Furthermore, possible changes in its traffic under metabolic challenges are unknown. The present study investigated the catalytic activity attributable to EC 3.4.11.3 in HDM, LDM and MF from isolated adipocytes of healthy (C), food deprived (FD) and monosodium glutamate (MSG) obese rats on aminoacyl substrates with N-terminal Cys or Leu, in absence or presence of insulin. Efficacy and reproducibility of subcellular adipocyte fractionation procedure were demonstrated. Comparison among HDM vs LDM vs MF intragroup revealed that hydrolytic activity trafficking from LDM to MF under influence of insulin in C, MSG and FD is only on N-terminal Cys. In MSG the same pattern of anterograde traffic and aminoacyl preference occurred independently of insulin stimulation. The pathophysiological significance of IRAP in adipocytes seems to be linked to comprehensive energy metabolism related roles of endogenous substrates with N-terminal cysteine pair such as vasopressin and oxytocin.
authors.affiliation: Laboratory of PharmacologyUnit of Translational Endocrine Physiology and PharmacologyInstituto Butantan, Avenue Vital Brasil, 1500, CEP05503-900 Sao Paulo, BrazilDepartment of PhysiologyUniversidade de Sao Paulo, Sao Paulo, Brazil Laboratory of PharmacologyUnit of Translational Endocrine Physiology and PharmacologyInstituto Butantan, Avenue Vital Brasil, 1500, CEP05503-900 Sao Paulo, BrazilDepartment of PhysiologyUniversidade de Sao Paulo, Sao Paulo, Brazil Laboratory of PharmacologyUnit of Translational Endocrine Physiology and PharmacologyInstituto Butantan, Avenue Vital Brasil, 1500, CEP05503-900 Sao Paulo, BrazilDepartment of PhysiologyUniversidade de Sao Paulo, Sao Paulo, Brazil.
authors.forename: Rafaela Fadoni
authors.initials: RF
authors.lastname: Alponti
authors.affiliation: Laboratory of PharmacologyUnit of Translational Endocrine Physiology and PharmacologyInstituto Butantan, Avenue Vital Brasil, 1500, CEP05503-900 Sao Paulo, BrazilDepartment of PhysiologyUniversidade de Sao Paulo, Sao Paulo, Brazil.
authors.forename: Luciana Godoy
authors.initials: LG
authors.lastname: Viana
authors.affiliation: Laboratory of PharmacologyUnit of Translational Endocrine Physiology and PharmacologyInstituto Butantan, Avenue Vital Brasil, 1500, CEP05503-900 Sao Paulo, BrazilDepartment of PhysiologyUniversidade de Sao Paulo, Sao Paulo, Brazil.
authors.forename: Norma
authors.initials: N
authors.lastname: Yamanouye
authors.affiliation: Laboratory of PharmacologyUnit of Translational Endocrine Physiology and PharmacologyInstituto Butantan, Avenue Vital Brasil, 1500, CEP05503-900 Sao Paulo, BrazilDepartment of PhysiologyUniversidade de Sao Paulo, Sao Paulo, Brazil Laboratory of PharmacologyUnit of Translational Endocrine Physiology and PharmacologyInstituto Butantan, Avenue Vital Brasil, 1500, CEP05503-900 Sao Paulo, BrazilDepartment of PhysiologyUniversidade de Sao Paulo, Sao Paulo, Brazil paulo.silveira@butantan.gov.br.
authors.forename: Paulo Flavio
authors.initials: PF
authors.lastname: Silveira
mesh_terms: D017667:Adipocytes / Q000378:metabolism*; D000626:Aminopeptidases / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D003545:Cysteine / Q000378:metabolism*; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D007328:Insulin / Q000378:metabolism*; D008297:Male; D009765:Obesity / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results
chemical_list: D007328:Insulin; D000626:Aminopeptidases; D003545:Cysteine
keywords: adipocyte; aminopeptidases; diet; insulin; obesity