Beclin 1 knockdown reduces ALK5 protein levels. a Representative image of CF1 hippocampal neurons stained for beclin 1 and ALK5. Intensity trace (offset white line) is plotted at right. b Quantification of ALK5 fluorescence intensity in CF1 hippocampal cells infected with ctrl or beclin 1 shRNA. Only GFP+ infected cells were analyzed. Data are combined results from two independent experiments. Each dot represents a single cell (n = 37–41 total cells from 20 different fields/group). Data were analyzed by unpaired Student’s t-test, ***p ≤ 0.001. c Representative western blot of lysates from infected CF1 forebrain neurons. d Quantification of ALK5 and e TBRII protein levels normalized to NSE. Data are combined results of three independent experiments analyzed by unpaired t-test. *p ≤ 0.05. f ALK5 and g TBRII mRNA levels were measured by RT-PCR and levels were normalized to GAPDH. Relative levels were calculated using the ΔΔCt method. Data are combined results from three independent experiments. Data were analyzed by unpaired Student’s t-test. All bar graphs are mean ± SEM.