SNX12 affects β-processing of APP but not BACE1 level or activity. SH-SY5Y cells were transfected with (A) SNX12 and control plasmids, or (B) two SNX12 siRNAs (1 and 2) and a control scrambled siRNA. sAPPβ in conditioned media and total APP, APP βCTF and BACE1 in cell lysates were analyzed by Western blot. (C) HEK 293 T cells were first transfected with APP ΔC57. After splitting equally, cells were transfected with SNX12 (+) or control (−) plasmids. Transfected APP ΔC57 and SNX12 in cell lysates were analyzed by Western blot. Aβ42 in conditioned media were assayed by ELISA. N = 4, *: p < 0.05. (D) SH-SY5Y cells were transfected with SNX12 and control plasmids. Cell lysates were assayed for BACE1 activity using a commercial kit. N = 3.