Extended Data Fig. 5: NFYB-1 regulates specific lipid species via SPP-8 (Related to Fig. 4).

a, Absolute levels of respective ceramides species normalized to protein levels detected by targeted lipidomic analysis of day 1 isp-1(qm150) and isp-1(qm150);nfyb-1(cu13) on control and upon spp-8i in AL day 1 (N = 4, n ≥ 5000 per repeat per condition) (box plot represents line at median, using minimum and maximum of all of the data, error bar shows standard deviation above and below the mean of the data). b, Abundance of exogenously supplemented CER (ceramides) and CL (cardiolipins) as detected by Mass-spectrometry in AL day 1 (N = 1, n ≥ 1000). c, spp8i increases nonyl-acridine orange staining in AL day 1, indicating increased cardiolipin levels, quantitation by biosorter (n ≥ 400). d, Relative fold change in mRNA levels of cardiolipin synthesis genes measured by qPCR in indicated genotypes AL day1 (n ≥ 1000), e, Cardiolipin (CL) synthesis pathway. c-d, All data represent N = 3 independent biological replicates, n = total worms per condition from three replicates unless stated otherwise. Error bar shows mean ± s.e.m, statistics determined by a and c, one-way ANOVA and d, two-sided t-test ns: not significant, *P < 0.5, **P < 0.01, ***P < 0.001. f, NFYB-1 coordinates organellar activities: Transcription factor NFYB-1 promotes nuclear localization of UPR^mt factors DVE-1 and ATFS-1, maintains cardiolipin levels and facilitates the mitochondria to cytosolic stress response (MCSR). Concurrently NFYB-1 limits ER associated genes, ER stress and lysosomal prosaposin. This state results in normal mitochondrial function and longevity. nfyb-1 loss (NFYB-1 KO) activates ER stress, partially disrupts UPR^mt factors, and MCSR. NFYB-1 activates lysosomal prosaposin/SPP-8, leading to fragmented mitochondria, reduction of oxygen consumption, altered ceramide (CER) and cardiolipin (CL) levels, resulting in abolishment of mitochondrial longevity.