Cells were homogenized in hypotonic Tris buffer (10mM Tris, 0.2 mM MgCl
2, PH 7.4) containing protease and phosphatase inhibitor cocktail using a probe sonicator, followed by centrifugation at 12,000 rpm for 15 min at 4° C. The resultant supernatant was used for the immunoblot analysis. Protein concentration was quantified using protein assay reagent (Solarbio, Beijing, China). Equal amounts of protein were resolved by SDS-PAGE gel and electrotransferred to nitrocellular membranes. After blocking, membranes were blotted overnight at 4° C with primary antibodies. Primary antibodies used include
anti phospho-eIF2-α (1:1,000, #3398, Cell Signaling Technology, Beverly, MA, USA),
anti-eIF2-α (1:1,000, #5324, Cell Signaling Technology),
anti-ATF4 (1:1,000, ab85049, Abcam),
anti-CHOP (1:1,000, #2895, Cell Signaling Technology),
anti-caspase-3 (1:1000, #9662, Cell Signaling Technology),
anti-cleaved-caspase-3 (1:1,000, #9664, Cell Signaling Technology), and
anti-GAPDH (1:1,000, #5174, Cell Signaling Technology) antibodies. After incubation with HRP-conjugated secondary antibodies, membranes were developed with enhanced chemiluminescence (Thermo Fisher Scientific) using
KODAK Image Station 4000MM PRO. Membranes were reblotted with
anti-GAPDH for normalization. Densitometric analysis of immunoblots was performed using Image J software.
Ying Y., Xue R., Yang Y., Zhang S.X., Xiao H., Zhu H., Li J., Chen G., Ye Y., Yu M., Liu X, & Zhong Y. (2021). Activation of ATF4 triggers trabecular meshwork cell dysfunction and apoptosis in POAG. Aging (Albany NY), 13(6), 8628-8642.