CPT2 K79 acetylation causes acylcarnitine accumulation and mitochondrial damage. (A) The mass spectrometry identification map of CPT2 K79 acetylation in stored human platelets. (B) The changes in CPT2 K79 acetylation levels in human platelets during storage were detected by western blot analysis using an anti-CPT2 K79 acetylation antibody and anti-CPT2 antibody. The specificity of this anti-CPT2 K79 acetylation antibody is evaluated in supplemental Figure 4. (C) Apoptosis and mtROS levels were detected by flow cytometry in the 293T cell line stably expressed human CPT2 (CPT2) or the 2 mutants of CPT2, K79Q (KQ) and K79R (KR). n = 3. (D) The levels of C16:0 and C18:0 acylcarnitine in CPT2, KQ, and KR 293T cells were measured. n = 3. (E) OCR was measured by Seahorse in CPT2, KQ, and KR cells or treated with 20 µM palmitoylcarnitine (PCT). (F) Basal, ATP-linked, and maximal oxygen consumption levels are represented. n = 3. (G) Representative micrograph of the mitochondria by transmission electron microscopy in CPT2, KQ, and KR cells or treated with 20 µM PCT, respectively. Scale bars represent 1 µm. (H) CPT2 K79Q mice were generated and OCR was measured in WT and KQ MEF cells using 200 µM palmitate + 300 µM l-carnitine as a substrate. (I) Apoptosis, MMP, and mtROS levels were evaluated in stored WT or KQ platelets. n = 3. (J) The survival of WT or KQ platelets stored for 1 day in vivo posttransfusion to WT mice were measured by flow cytometry. n = 3. *P < .033, **P < .0021, ***P < .0002, ****P < .0001.