Fig. 4: PTPIP51 regulates metabolic processes during HCMV infection.
A Top: Abundance of PTPIP51-VDAC interaction quantified by targeted MS (≥ 2 peptides per protein). Bottom: Cartoon representation of the role of VDAC1/2/3 proteins in calcium import in the mitochondria (brown/orange) from the ER (blue). B Top: Abundance of PTPIP51 interaction with the electron transport chain complex (ETC) subunits and ETC assembling proteins (*) (2 biological replicates, except for 24 hpi). Bottom: Cartoon representation of the ETC complex that PTPIP51 interacting proteins stabilize. C Quantification of respiratory parameters in mock or 72 hpi HCMV-infected cells following siRNA control (siCTRL) or PTPIP51 KD (siPTPIP51). Left: Radar plot displaying all of the scaled respiratory parameters measured by the Seahorse assay. Right: Bar plots of basal and maximal respiration in these conditions (siGFP = 5, siPTPIP51 = 4 biological replicates). Exact p values; Basal: siGFP vs. siPTP = 3.12E-04; Maximal: siGFP vs. siPTP = 0.005. D Quantification of membrane potential (ΔΨm) of MENC and non-MENC mitochondria. TMRE intensity is normalized to the mito-BFP signal and then scaled to the average membrane potential for each cell. Each data point represents a single cell; 10 cells per replicate; n = 3 biological replicates, 90 mitochondria across 30 cells. Boxplot shows the median as well as upper and lower quartiles of the data with the whiskers showing the full distribution, excluding outliers. Exact P values; TMRE Intensity: MENC vs. Non-MENC = 8.32E-07. ΔΨm mitochondria membrane potential. E Left: Representative microscopy images showing mitochondria undergoing peripheral fission, leading to MENC (top) or non-MENC (bottom). Scale bar = 3 µm. Right: Median TMRE intensity in the progeny is quantified every frame (5 s) for 35 s after fission and plotted as log2 fold change to TMRE intensity during fission, when time = 0. TMRE intensity was first normalized to mito-BFP. ΔΨm mitochondria membrane potential, hpi hours post infection, mito mitochondria, ER endoplasmic reticulum, s seconds, M mock, MENC mitochondria–ER encapsulation, KD knockdown, ETC electron transport chain, Ca2+ calcium, OCR oxygen consumption rate. Data are presented as mean values with 95% confidence intervals. Black asterisks indicate statistical comparison to uninfected cells, while green asterisks indicate comparison between conditions at the same timepoint. *P ≤ 0.05, **P ≤ 0.01, and ***P ≤ 0.001 using a Welch’s t test. Source data are provided as a Source Data file.
