title: Signaling mechanisms underlying the insulin-sensitizing effects of adiponectin.
abstract: Adiponectin is an insulin-sensitizing adipokine with protective effects against a cluster of obesity-related metabolic and cardiovascular disorders. The adipokine exerts its insulin-sensitizing effects by alleviation of obesity-induced ectopic lipid accumulation, lipotoxicity and chronic inflammation, as well as by direct cross-talk with insulin signaling cascades. Adiponectin and insulin signaling pathways converge at the adaptor protein APPL1. On the one hand, APPL1 interacts with adiponectin receptors and mediates both metabolic and vascular actions of adiponectin through activation of AMP-activated protein kinase and p38 MAP kinase. On the other hand, APPL1 potentiates both the actions and secretion of insulin by fine-tuning the Akt activity in multiple insulin target tissues. In obese animals, reduced APPL1 expression contributes to both insulin resistance and defective insulin secretion. This review summarizes recent advances on the molecular mechanisms by which adiponectin sensitizes insulin actions, and discusses the roles of APPL1 in regulating both adiponectin and insulin signaling cascades.
authors.affiliation: Department of Medicine, The University of Hong Kong, Hong Kong; Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Hong Kong.
authors.forename: Kenneth K Y
authors.initials: KK
authors.lastname: Cheng
authors.affiliation: Department of Medicine, The University of Hong Kong, Hong Kong; Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Hong Kong.
authors.forename: Karen S L
authors.initials: KS
authors.lastname: Lam
authors.affiliation: Department of Medicine, The University of Hong Kong, Hong Kong.
authors.forename: Baile
authors.initials: B
authors.lastname: Wang
authors.affiliation: Department of Medicine, The University of Hong Kong, Hong Kong; Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Hong Kong; Department of Pharmacology & Pharmacy, The University of Hong Kong, Hong Kong. Electronic address: amxu@hku.hk.
authors.forename: Aimin
authors.initials: A
authors.lastname: Xu
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing / Q000502:physiology; D052242:Adiponectin / Q000502:physiology*; D000818:Animals; D006801:Humans; D007328:Insulin / Q000378:metabolism / Q000502:physiology*; D007333:Insulin Resistance / Q000502:physiology; D000078790:Insulin Secretion; D009765:Obesity / Q000503:physiopathology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D054419:Receptors, Adiponectin / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: C464801:APPL1 protein, human; D048868:Adaptor Proteins, Signal Transducing; D052242:Adiponectin; D007328:Insulin; D054419:Receptors, Adiponectin; D051057:Proto-Oncogene Proteins c-akt; D055372:AMP-Activated Protein Kinases
keywords: APPL1; adiponectin; diabetes; insulin; obesity