Synaptotagmins family affect glucose transport in retinal pigment epithelial cells through their ubiquitination-mediated degradation and glucose transporter-1 regulation

Figure 2 Synaptotagmins 4 promotes high glucose-induced cellular glucose uptake by ARPE-19 cells. A: The expression of synaptotagmins 4 (SYT4) was detected via Western blot; B: Apoptosis was observed by flow cytometry; C: A Cell Counting Kit-8 assay was used to determine cell viability; D: Flow cytometry was used to determine intracellular Ca²⁺ levels; E: Glucose uptake levels were determined; F: Western blot was used to detect the glucose transporter; G: Immunofluorescence analysis was used to examine the extent of GLUT1 membrane translocation; H: The levels of inflammatory cytokines [tumour necrosis factor alpha, interleukin (IL)-1β, and IL-6] were measured via ELISA. ^aP < 0.05, ^bP < 0.001, vs the NC group; ^cP < 0.01, ^dP < 0.01 vs the NC group, HG group. SYT: Synaptotagmins; GLUT1: Glucose transporter-1; TNF-α: Tumour necrosis factor alpha; IL: Interleukin.