Figure 8.

Two-dimensional class averages obtained from negative-stain images of insulin-bound nanodisc-embedded holo insulin receptor. (A) Apo holo-receptor showing the characteristic Λ-shaped conformation assembled either into one or two nanodiscs (1U and 2U, respectively). (B) Insulin-complex holo-receptor assembled into nanodiscs after complexation with insulin. All display incorporation into a single nanodisc, suggesting that insulin binding permits or directs the combination of the ectodomain's membrane proximal elements. Arrows are the blobs putatively corresponding to the tyrosine kinase domain(s). The class averages reflect either a T-shaped conformation (1T) or a narrower conformation with two legs visible (II), the latter may in some instances be a side view of the 1T conformation. Based on Figure 3 in Gutmann et al. (2018) J Cell Biol 217, 1643-9 (https://doi.org/10.1083/jcb.201711047) and used under a Creative Commons License.