Figure 3. Charge reversal mutations in STX1A’s JMD manifest position-specific effects on the molecular weight of STX1A.

(A) Example image of SDS-PAGE of the electrophoretic analysis of lysates obtained from STX1-null neurons transduced with different STX1A JMD charge reversal mutations. (B) Quantification of the STX1A band pattern on SDS-PAGE of neuronal lysates through assignment of arbitrary hierarchical numbers from 1 to 6 based on the distance traveled, where number 1 represents the lowest single band as in STX1A^K260E and number 6 represents the highest single band as in STX1A^WT.(C) Quantification of the STX1A weighed band intensity of neuronal lysates for which the lowest band was arbitrarily assigned by 1 × and the highest band was assigned as 100 × and multiplied by the measured intensity of the STX1A bands. (D) Example image of SDS-PAGE of the electrophoretic analysis of lysates obtained from HEK293 cells transfected with different STX1A JMD charge reversal mutations. (E) Quantification of the STX1A band pattern on SDS-PAGE of HEK293 cell lysates as in (B). (F) Quantification of the STX1A weighed band intensity on SDS-PAGE of HEK293 cell lysates as in (C). (G) Correlation of the excitatory postsynaptic current (EPSC) amplitude normalized to that of STX1A^WT to the western blot (WB) band position of STX1A charge reversal mutation. (H) Correlation of the readily releasable pool (RRP) charge normalized to that of STX1A^WT to the WB band position of STX1A charge reversal mutation.(I) Correlation of vesicular probability (Pvr) normalized to that of STX1A^WT to the WB band position of STX1A charge reversal mutation. (J) Correlation of the miniature excitatory postsynaptic current (mEPSC) frequency normalized to that of STX1A^WT to the WB band position of STX1A charge reversal mutation. Data information: in (C, F, and G–J), data points represent mean ± SEM. Red lines in all graphs represent the STX1A^WT level. The numerical values are summarized in source data.