PLAAT1 expression triggers fragmentation of mitochondria in an enzyme activity-dependent manner.

This article focuses on the role of phospholipase A and acyltransferase 1 (PLAAT1), a member of the PLAAT protein family, in regulating mitochondrial morphology and peroxisome abundance in mammalian cells. Using doxycycline-inducible expression in HEK293 cells, the study demonstrates that overexpression of enzymatically active PLAAT1 induces mitochondrial fragmentation and reduces peroxisome numbers, effects not observed with a catalytically inactive mutant. PLAAT1 localizes to the outer mitochondrial membrane and alters the balance of mitochondrial fission and fusion proteins, suggesting its involvement in mitochondrial biogenesis and mitophagy. The findings indicate that PLAAT1 enzymatic activity is necessary for these organelle-specific effects, distinguishing its function from that of PLAAT3, another family member primarily affecting peroxisomes without altering mitochondrial morphology.