Fig. 2: FASN activated by caspase cleavage limits pan-stress responses independent of palmitate synthesis.
From: Proteolytic activation of fatty acid synthase signals pan-stress resolution
a, Expression of HSP-4p::GFP by caspase active-site mutation G360S. b, Highly conserved FASN domains and fragments used for in vitro caspase cleavage analyses. Enzymatic domains indicated with square boxes. Ce, C. elegans; Hs, H. sapiens. c,d, CED-3 in vitro cleavage of 35S-labelled C. elegans FASN-1 fragments (c), the DYMD to DYME mutation (D/E) in fragment 2 blocks CED-3 cleavage (d). Red asterisks indicate cleaved products; black asterisks indicate full-length molecules. e, Conserved cleavage. 35S-labelled human FASN is also cleaved in fragment 2 by caspase-3 producing a stable CTF similar to C. elegans. Casp, caspase-2, caspase-3 and caspase-8 as indicated for each lane. f, Cleavage-resistant fasn-1(D/E) C. elegans mutant phenocopies ced-3(-) mutant for enhanced inductions of ER, Osmotic and ROS stress reporters. g, Measurement of palmitate synthesis using 50% deuterated water (D2O) labelling for 16 h in the presence or absence of ER stress. m + 0, unlabelled palmitate; m + 1, deuterium-labelled palmitate representing newly synthesized palmitate. n = 3 biological replicates for each. Mean ± s.d. h, HSP-4p::GFP expression under ER stress with palmitate supplementation. Each circle represents one animal (a,f,h). Mean pixel intensity of each animal was normalized to mean value of WT without stress and plotted as FC. Violin plots show median (solid line) with quartiles (dashed line). For a, n = 40 animals for each genotype. n = 30 animals for each condition (f,h). P values were calculated using a two-tailed Mann–Whitney U-test. Cleavage assays (c–e) were repeated twice independently with similar results.
