Fig. 3: Mitochondrial KMT9 fuels PCa cell proliferation via regulation of de novo lipogenesis.

a–c Proliferation of DU145 cells transfected with siCtrl or siDLAT in combination with expression plasmid for LacZ (a, b), DLAT (a), or DLAT (K596R) (b) as indicated. Knockdown efficiency and expression of exogenous DLAT proteins was verified by Western blot (c). α-Tubulin served as loading control. d–i Proliferation of DU145 cells transfected with siCtrl or siKMT9α in combination with an expression plasmid for LacZ (d–h), KMT9α (d), MTS-KMT9α (e, g), NLS-KMT9α (f, g), or MTS-KMT9α (N122A), and NLS-KMT9α (N122A) (h). Knockdown efficiency and expression of exogenous KMT9α proteins was verified by Western blot (i). α-Tubulin served as loading control. j Proposed mechanism for KMT9-mediated control of mitochondrial functions in PCa cells. KMT9 monomethylates DLAT at K596, which is required for PDC activity and mitochondrial metabolism. KMT9 depletion abolishes DLAT K596 monomethylation, thereby impairing PDC activity and mitochondrial metabolism in PCa cells. k, l Free fatty acid (FFA) (k) and triglyceride (l) levels in DU145 cells transfected with siCtrl or siKMT9α in combination with expression plasmid for LacZ, NLS-KMT9α, MTS-KMT9α, or MTS-KMT9α (N122A). m, n Proliferation of DU145 (m) or HepG2 (n) cells transfected with sub-optimal concentrations of siCtrl or siKMT9α in the presence or absence of 100 µM SB204990 to detect potential effects of co-treatment. a, b, d–h, k–n, Data are presented as mean ± SD (a, b, d–h, m, n, n = 4 biological replicates) or mean + SD (k, l, n = 3 biological replicates). Statistical significance was determined by a two-sided Student’s t-test (a, b, d–h, k–n). All experiments were independently repeated at least three times with similar results. Source data are provided as a Source Data file.