Figure 8.
Mint3 expression levels impact the rate of secretion of Aβ1-40. HEK293 cells were transiently transfected with either empty vector (control) or vectors directing expression of human Mint1, Mint2, or Mint3. The medium was changed the next day and collected for analysis 48 h later. (A) Conditioned media from cells expressing the different Mints were assayed for Aβ1-40, as described under Materials and Methods. Values represent Aβ1-40 levels relative to controls (mean ± 1 SD; n = 3; **p < 0.001). (B) Cells were transfected with equal amounts of the control or Mint3-siRNA plasmids on day 0 and again on day 3 to maximize knockdown of the protein. Media were replaced on day 4 and conditioned media collected on day 6 for determination of Aβ1-40 levels (n = 3; *p < 0.01). (C) Cells were treated as described in B, and the level of expression of Mint3 was determined in cell lysates (20 μg/lane) by immunoblotting, with α-tubulin used as a loading control. Triplicates are shown of control and Mint3-depleted cell lysates.