Asb6, an Adipocyte-specific Ankyrin and SOCS Box Protein, Interacts with APS to Enable Recruitment of Elongins B and C to the Insulin Receptor Signaling Complex

• DOI: 10.1074/jbc.m406101200
• Publication Date: 2004-07-02T00:12:54Z
• Authors: Andrew Wilcox; Kostas D. Katsanakis; Farheen Bheda; T.S. Pillay
• Keywords: 3T3-L1; Insulin receptor substrate; GRB10

The APS adapter protein plays a pivotal role in coupling the insulin receptor to CAP and c-Cbl phosphatidylinositol 3-kinase-independent pathway of insulin-stimulated glucose transport. Yeast two-hybrid screening 3T3-L1 adipocyte library using as bait identified 418-amino acid ankyrin SOCS (suppressor cytokine signaling) box Asb6 an interactor. is orphan member larger family Asb proteins that are ubiquitously expressed. However, expression appears be restricted adipose tissue. was specifically expressed adipocytes 50-kDa but not fibroblasts. In Chinese hamster ovary-insulin (CHO-IR) cells Myc epitope-tagged interacted constitutively with FLAG-tagged presence or absence stimulation did alter interaction. adipocytes, activation accompanied by APS-dependent recruitment Asb6. appear undergo tyrosine phosphorylation. Immunofluorescence confocal microscopy studies revealed colocalized CHO adipocytes. immunoprecipitation Elongin BC complex found bound Asb6, required facilitate along Elongins B/C. Prolonged resulted degradation when co-expressed We conclude functions regulate components signaling facilitating BC.