Fig. 1 |. OPA1 is required for T_H17 cell effector function.

a, Representative live-cell spinning disk microscopy images showing mitochondria (GFP, green) and nuclei (Hoechst 42, blue) in CD4⁺ T cells from PhAM mice cultured in T helper (T_H) and T_reg cell conditions on day 4. Two separate experiments. b, Immunoblot of OPA1, MFN2, MFN1, DRP1 (left) and ratio of l- and s-OPA1 isoforms (right) in T_N, T_H and T_reg T cells on day 4. Tubulin is used as a sample processing control. c, Kinetics of OPA1 isoforms during T_H and T_reg differentiation. In b,c, T_H1, T_H2 and T_H17: n = 5 biological replicates, T_reg: n = 4 biological replicates and 3 independent experiments. d, Electron microscopy (left) and width of mitochondrial cristae (right). Control T_H1: n = 442, control T_H2: n = 401, control T_H17: n = 418, control T_reg: n = 421, Opa1^Cd4-cre T_H1: n = 615, Opa1^Cd4-cre T_H2: n = 786, Opa1^Cd4-cre T_H17: n = 554 and Opa1^Cd4-cre T_reg: n = 433 cristae, and 3 biological replicates. Data are shown as individual measurements and geometric mean (red bar). e, Left, oxygen consumption rate (OCR) on addition of oligomycin (oligo), fluoro-carbonyl cyanide phenylhydrazone (FCCP) and rotenone plus antimycin A (Rot + AA) (n = 7 injections, 3 biological replicates). Right, baseline OCR, ATP-coupled respiration and maximal respiration (n = 3 independent experiments). f, Basal glycolytic rate and total glycolytic capacity (n = 4 biological replicates), measured by extracellular acidification rate (ECAR). g, Cells expressing IFNγ, 1L-17A, GATA3 and FOXP3 following restimulation (n = 4 biological replicates). The percentage of cells in each quadrant is indicated. h, Heat map of cytokine expression in the supernatant of indicated cells types, shown as log₂ fold change (FC) (n = 3 biological replicates). i, TBET and ROR-γT expression (n = 4 biological replicates). gMFI, geometric mean fluorescence intensity. Representative plots and graphs summarize results of at least two independent experiments except where noted otherwise. Data in b,c,e-g,i are mean ± s.e.m. Two-sided Tukey’s test (b,d), Dunnett’s test (c), Šidak’s test (e,f) or unpaired two-tailed f-test (g,i). Exact P-values are indicated.