Spacing within and between mitochondrial cristae is differentially altered by Tg-induced ER stress in fragmented and elongated populations. (A) Representative membrane surface reconstructions of elongated (left) and fragmented (right) mitochondria in MEF^mtGFP cells treated with Tg (500 nM, 8 h) showing subdivision of IMM compartments (IBM, tan; junction, cyan; crista, purple) as defined by OMM–IMM distance. The OMM surface is represented as a transparent gray mesh. (B) Enlarged inset of boxed region in elongated example from A showing surface membrane reconstruction colored by inner membrane compartments defining intra- and intercrista and junction measurements. (C) Combined histogram of intracrista membrane distances of elongated (top) and fragmented (middle) mitochondria in MEF^mtGFP cells treated with vehicle and Tg. Dashed vertical lines correspond to peak histogram values of pooled data. Graph (bottom) showing peak histogram values from each mitochondrion within each corresponding treatment and mitochondrial morphology class. Quantifications from vehicle elongated n = 20, Tg elongated n = 18, vehicle fragmented n = 11, and Tg fragmented n = 15 mitochondria are shown. P values from Mann–Whitney U test are indicated. *P < 0.05; ***P < 0.005. (D) Combined histogram of intrajunction membrane distances of elongated (top) and fragmented (middle) mitochondria in MEF^mtGFP cells treated with vehicle and Tg. Dashed vertical lines correspond to peak histogram values of pooled data. Graph (bottom) showing peak histogram values from each mitochondrion within each corresponding treatment and mitochondrial morphology class. Quantifications from vehicle elongated n = 20, Tg elongated n = 18, vehicle fragmented n = 11, and Tg fragmented n = 15 mitochondria are shown. P values from Mann–Whitney U test are indicated. *P < 0.05.