CgANT2 regulates mitophagy of oyster haemocyte response against bacterial stimulation

Abstract

Adenine nucleotide translocator (ANT) is a major molecule in the inner membrane of mitochondria that plays an important role in regulating mitophagy. In the present study, a conserved ANT2 homologue (designated as CgANT2) was identified and functionally characterized in oyster Crassostrea gigas. There were three typical Mito_carr tandem repeats in CgANT2. The mRNA expression levels of CgANT2 in haemocytes increased significantly at 24 and 72 h after Vibrio splendidus stimulation. Its protein was abundantly expressed in granulocytes and was observed to be colocalized with mitochondria. When CgANT2 expression was suppressed by injection with its dsRNA, there was an increased mitochondrial reactive oxygen species (mtROS) production and mitochondrial permeability transition pore (mPTP) opening, while the mRNA expression levels of mitophagy-related genes (CgPINK1 and CgParkin) and the percentage of mitophagy in haemocytes all decreased significantly. These results indicated that CgANT2 regulated mtROS production and mPTP opening, thereby inducing mitophagy in the oyster haemocyte response against V. splendidus stimulation.