Journal: EMBO Reports

Article Title: STREMI: a dual-function upstream ORF-encoded regulator of mitochondrial cristae architecture

doi: 10.1038/s44319-026-00783-8

Figure Lengend Snippet: ( A ) Detection of endogenous STREMI in HEK293T lysates using a rabbit polyclonal antibody against STREMI N-terminal residues 2–13. ( B ) Immunostaining of STREMI and the mitochondrial marker TOM20 in transfected HeLa cells. Scale bar, 10 µm. ( C ) Oxygen consumption rate (OCR) measured in scramble (SCR) control and STREMI knockout (KO) HEK293T cells during a mitochondrial stress test using a Seahorse XFe96 analyzer. Treatments: oligomycin (Oligo), carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone (FCCP), rotenone/antimycin A (Rot/AA). Data are presented as mean ± SEM ( n = 8). ( D ) Basal respiration, maximal respiration (Max Res), spare respiratory capacity (Spare RC), and ATP production (ATP Pro) of SCR control and STREMI KO cells measured in the mitochondrial stress test. Data are presented as mean ± SEM ( n = 8). Basal respiration ( P = 3.6 × 10 − 3 ), Max Res ( P = 2.6 × 10 − 3 ), Spare RC ( P = 3.6 × 10 − 3 ), and ATP Pro ( P = 4.8 × 10 − 3 ). P values are from two-tailed unpaired t tests. ( E ) Volcano plot of proteins enriched in STREMI immunoprecipitation (IP) versus EGFP control, identified by mass spectrometry (MS) ( n = 3). P values are from two-tailed unpaired t tests and Benjamini–Hochberg-adjusted. ( F ) Immunoblot analysis of interactions between MICOS subunits and StrepII-STREMI following immunoprecipitation via the StrepII tag. ( G ) StrepII-tagged MIC10 was immunoprecipitated from HEK293T cell mitochondria, followed by immunoblotting of MICOS subunits and STREMI. ( H ) Immunogold detection of endogenous STREMI in HeLa cells. Scale bar, 200 nm. The arrows point to the position of gold particle. ( I ) The histograms show the fraction of gold particles within the indicated distance to the crista junction in nanometers in HeLa cells. ( J , K ) Representative transmission electron microscopy (TEM) images of mitochondria from SCR control ( J ) and STREMI KO ( K ) HeLa cells. ( L ) Quantitative analysis of mitochondrial cristae morphology in SCR control and STREMI KO HeLa cells. Bar chart depicts the percentage of cristae classified as (1) lamellar, (2) swollen, (3) irregular, (4) onion-shaped, or (5) other aberrant shapes, based on TEM ( n = 237 mitochondria for scramble control; n = 265 mitochondria for STREMI KO, 5 biological replicates). P values were calculated using Fisher’s exact test based on raw counts ( P < 1 × 10 − ⁴). ( M ) Cristae junction (CJ) abundance in SCR control and STREMI KO HeLa cells, quantified by TEM. Data are presented as mean ± SEM ( n = 228 mitochondria for scramble control; n = 213 mitochondria s for STREMI KO, 5 biological replicates). P values from two-tailed unpaired t tests ( P < 1 × 10 − ⁴). ( N ) Stimulated emission depletion (STED) nanoscopy of live HeLa cells stained with PK Mito-Orange dye. Scale bar, 5 μm. .

Article Snippet: Rabbit polyclonal anti-SDHA(WB 1:5000) , AB Clonal , Cat#A2594 RRID:AB_2764479.

Techniques: Immunostaining, Marker, Transfection, Control, Knock-Out, Two Tailed Test, Immunoprecipitation, Mass Spectrometry, Western Blot, Transmission Assay, Electron Microscopy, Staining