Expression and modulation of TUB by insulin and thyroid hormone in primary rat and murine 3T3-L1 adipocytes.
tub encodes a protein of poorly understood function, but one implicated strongly in the control of energy balance and insulin sensitivity. Whilst tub expression is particularly prominent in neurones it is also detectable in extraneuronal tissues. We show here, for the first time, expression of TUB protein in rat adipocytes and the murine adipocyte model 3T3-L1 and demonstrate that insulin induces its tyrosine phosphorylation and association with the insulin receptor. TUB expression is regulated developmentally during adipogenic differentiation of 3T3-L1 cells and in response to cell treatment with thyroid hormone or induction of insulin resistance. TUB was upregulated 5- to 10-fold in adipocytes from obese Zucker rats and 3T3-L1 adipocytes that had been rendered insulin resistant, a response that could be antagonised by rosiglitasone, an insulin-sensitising drug. Our data are consistent with a previously unforeseen role for TUB in insulin signalling and fuel homeostasis in adipocytes.
Stretton
Clare
C
Division of Molecular Physiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
Litherland
Gary J
GJ
Moynihan
Audrey
A
Hajduch
Eric
E
Hundal
Harinder S
HS
D041721:3T3-L1 Cells; D048868:Adaptor Proteins, Signal Transducing; D017667:Adipocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D050156:Adipogenesis; D000818:Animals; D007328:Insulin / Q000378:metabolism* / Q000494:pharmacology; D008297:Male; D051379:Mice; D009765:Obesity / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011924:Rats, Zucker; D014284:Triiodothyronine / Q000378:metabolism* / Q000494:pharmacology
D048868:Adaptor Proteins, Signal Transducing; D007328:Insulin; D011506:Proteins; C546203:TUB protein, rat; C098988:Tub protein, mouse; D014284:Triiodothyronine