GCN5L1/BLOS1 Links Acetylation, Organelle Remodeling, and Metabolism

General control of amino acid synthesis 5 (GCN5) like-1 (GCN5L1) was identified as a novel gene with sequence homology to the histone acetyltransferase Gcn5. Subsequent protein-interaction studies identified GCN5L1 as a subunit of the multiprotein lysosome biogenesis complex, resulting in an alternative designation as biogenesis of lysosome-related organelle complex 1 subunit 1 (BLOS1 or BLOC1S1). Despite the distinct nomenclatures, GCN5L1/BLOS1 has been shown to play crucial roles in mitochondria, endosomes, lysosomes, and synaptic vesicle precursors (SVPs). GCN5L1/BLOS1 controls mitochondrial protein acetylation, modulates metabolic pathways, and orchestrates retrograde mitochondria-to-nucleus signaling. It also contributes to endosome–lysosome and vesicle trafficking and to endolysosomal function. Here we discuss the intracellular roles of GCN5L1/BLOS1 in the hope of linking mitochondria-centric effects to cytosolic vesicle biology.