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. 2020 Apr 16;105(7):2354–2366. doi: 10.1210/clinem/dgaa190

Figure 6.

Figure 6.

The mutant Met482-Leu483del NPR-B has lower basal and CNP-stimulated cGMP-synthesis activity compared with the previously published mutant Arg655Cys NPR-B. (A) Membrane NPR-B expression levels and (B) CNP (0.1 nM)-induced cGMP formation in fibroblasts cultured from a control donor or from the probands with either variant. (C) Western blot analysis of membrane NPR-B expression levels in HEK-293 cells expressing the Met482-Leu483del or Arg655Cys NPR-B mutants. NPR-B expression was normalized to Na+/K+-ATPase expression. (D and E) Guanylyl cyclase activity assays demonstrate that the mutant Met482-Leu483del NPR-B exhibits lower baseline enzymatic activity and lower cGMP responses to CNP compared with the mutant Arg655Cys. Crude membranes prepared from HEK-293 cells expressing either mutant were incubated with vehicle (-), CNP or detergent (1% Triton X-100). cGMP production was measured by radioimmunoassay. (E) Values are expressed as percent of the maximal Triton-induced activity (as 100%). Means ± SEM (n = 3); **P < 0.01. cGMP, cyclic guanosine monophosphate; CNP, C-type natriuretic peptide; NPR, natriuretic peptide receptor.