Involved in mitochondrial homeostasis, and control of oxidative phosphorylation and mitochondrial DNA (mtDNA) maintenance (PubMed:30833296). Non-selective channel that modulates the membrane potential under normal conditions and oxidative stress (By similarity). Widely expressed. Genetic defects resulting in MPV17 loss are responsible for the transparent (tra) mutant phenotype. 'tra' fishes display pigmentation abnormalities and lack of cells derived from the neural crest, such as iridophores and, at later stages of development, melanophores (PubMed:23862018). MPV17-null larvae show disruption of mitochondrial ultrastructure in liver cells with mitochondrial ballooning and disappearance of cristae, and impaired oxidative phosphorylation, insufficient pyrimidine synthesis, and mtDNA depletion (PubMed:30833296). Belongs to the peroxisomal membrane protein PXMP2/4 family.