Figure 2: Identification and characterization of the MQs.
Strong cationic exchange chromatography of Dp (A) , Dj(B) and Dv (C) . Blue arrows indicate active fractions
on hV2R able to inhibit more than 50% of 3H-AVP
binding. (D) Binding of 3H-AVP on hV2R in the
presence of MQs (colored squares, for a comparison of the complete set
of toxins, see Supplementary Table 2), P19859 and Q5ZPJ7 (blue dashed
lines), Dtx-I (grey dots), Dtx-K (grey squares), calcicludine (pink open
circle), BPTI (light blue open circle) or five other non-active Kunitz
peptides (black symbols). α-DTX, MQ2, MQ4 and MQ5 curves are not shown
for clarity. (E) Toxin antagonist effect on cAMP production
induced by 1.77 nM of AVP on V2R (same color code than for panel D).
Dotted line corresponds to cAMP production with toxins in the absence of
AVP.
Table 1: Pharmacological properties of the V2R toxins. ND: not
done. The statistical significance was assessed for binding by a one-way
ANOVA with post hoc test according to Dunnett in comparison to MQ1. *: p
value=]0.0; 0.01]; **: p value=]0.01; 0.001]; ***: p value
< 0.001 and for cAMP inhibition by t-student in comparison to
MQ1 with ***: p value < 0.001. Means represent 2 to 25
independent experiments. MQ7-8: MQ7 + MQ8. Calci: calcicludine