Fig. 2.

CRT abrogates ERAD of IR from subject with congenital type A insulin resistance. (A) The Leu→Pro mutation at aa62 (*L62P) is in the first leucine-rich repeat domain (L1) of the IR. Protein domains in the IR include: leucine-rich repeat domains (L1 and L2), Cys-rich region, fibronectin type III domains (Fn₀, Fn₁, Fn₂) and Fn₁ insert, transmembrane (TM), juxtamembrane (JM), and tyrosine kinase (TK) domains, and carboxyl-terminal tail (CT). Furin recognition at the RKRR site cleaves the polypeptide into α and β subunits. (B) 293 cells were transfected with wild-type hIR or hIR^mut cDNA. Cell surface receptors were biotinylated and processed as described previously. (C) Cells were transfected with hIR^mut cDNA alone or with CRT cDNA and processed for Western blotting or for pulse–chase analysis (D), as described previously. P, pulse; C, chase.