Fig. 4: Mimicking phosphorylation at T2677 and Y2683 has opposing effects in modulating FLNCd24 homo- and hetero-dimerisation.
A Native mass spectra at 1 μM of FLNCd24 WT (middle) and the phosphomimics T2677D (left) and Y2683E (right) show differences in the relative abundances of the monomer (yellow) and dimer (red) (upper row). T2677D forms a stabilised homodimer, relative to WT; Y2683 a destabilised dimer. Native MS spectra at 5 μM of each of HSPB7ACD and either FLNCd24 WT or one of the phosphomimics (lower row). Heterodimers are the dominant species in each of the spectra, but a notable abundance of FLNC (red, and yellow) and HSPB7ACD (purple) can be observed in the case of the T2677D mutant, and to a lesser extent for WT and Y2683E. B Titration curves for homo- (upper) and hetero-dimerisation (lower). WT: red and medium grey; T2677D: salmon and light grey; Y2683D: burgundy and dark grey. Error bars represent ±1 standard deviation of the mean (n = 3). C Free energy diagram showing the differences in stability for homo- and heterodimers in each of the three forms of FLNC. The vertical thickness of the bars corresponds to the error in our estimates. Lower free energies correspond to higher stability. See also Supplementary Methods.
