At DIV 7, cultured primary neurons in 24 wells were washed once with 1X PBS, then fixed in 4% paraformaldehyde (PFA) in PBS at room temperature (RT) for 10 min. After three times washing with 1X PBS, cells were blocked with 10% normal donkey or goat serum in 1 X PBS for 30 min at RT followed by three times washing in 1 X PBS. Thereafter, cells were incubated with primary antibodies diluted in 1 X PBS containing 1% normal donkey or goat serum for 2–3 hr at RT. three times washing with 1 X PBS, incubated with appropriate secondary antibodies conjugated with
Alexa Fluor 488,
Alexa Fluor 555, or
Alexa Fluor 647 (1:500, Invitrogen) in 1 X PBS containing 1% normal donkey or goat serum for 1 hr at RT. Washed with 1 X PBS for three times, then counterstained the slides with
DAPI (1:2000, Sigma) and mounted by using
Vectashield (Vector) after rinsing. Primary antibodies used in this study were rabbit anti-APP (1:100, Synaptic Systems, 127 003),
mouse anti-rab5 (1:100, Synaptic Systems, 108011),
mouse anti-rab11a (1:20, Santa Cruz, sc-166523),
mouse anti- Golgin-97 (1:100, Invitrogen, A-21270),
rat anti-Lamp1 (1:20, Santa Cruz, sc-19992). After staining, images were obtained by using confocal microscope (Olympus
FV-1200 or Leica SP8). The percentage of APP or APP-ΔCRD co-localizing with rab5, rab11, Golgin-97 and Lamp1 was calculated using JACOP (Bolte and Cordelières, 2006 (
link)).
Liu T., Zhang T., Nicolas M., Boussicault L., Rice H., Soldano A., Claeys A., Petrova I., Fradkin L., De Strooper B., Potier M.C, & Hassan B.A. (2021). The amyloid precursor protein is a conserved Wnt receptor. eLife, 10, e69199.