Fig. 4: Axon repulsive activity of NELL2 correlates with its affinity towards Robo3.
From: NELL2-Robo3 complex structure reveals mechanisms of receptor activation for axon guidance
a, b Binding isotherms (a) for SPR experiments testing the interaction of mRobo3 FN1–3 with mNELL2 EGF1–6 WT and mutants. Original sensorgrams are in Supplementary Fig. 3d. SPR responses are fit with 1:1 Langmuir isotherm model to calculate dissociation constants (KD) (b). The ± errors represent standard error of the fit. DIC images of commissural axons exposed to mutant forms of NELL2 with Robo3-binding affinities of 1.7 µM (c) and ≥100 µM (d) (0 and 2 h). Commissural axons respond to NELL2 mutants with 1.7 µM binding affinity, but not with ≥100 μM affinity. (e) Quantification of commissural axon turning angles in response to wild-type NELL2 or NELL2 containing point mutations (n = 3 for WT NELL2, R452A, and L498A/F500A; n = 4 for R448A/Y450A; n = 5 for V509A). KD values are dissociation constants measured for mNELL2 mutants via SPR (b). Scale bar, 10 µm (c, d).
