Described are methods for inactivating adenine nucleotide transporter proteins in specific tissues of a transgenic nonhuman animal using a conditional knockin/knockout technology such as the Cre-LoxP, Flip-FLP recombinase, or Tet-on/off technologies. Specifically, the Ant2 gene is functionally inactivated in a mouse in liver, with or without the concurrent inactivation of the Ant1 gene. The result is an animal in which the Ant2 gene and accompanying ANT 2 protein is absent in one or more tissues, either in the presence or absence of the Ant1 gene and accompanying protein. The resulting animals, cells, mitochondria, and subcelluar fractions such as the mitochondrial permeability transition pore can then be used to identify agents that affect animal and/or subcellular function via a direct or indirect interaction with the ANT2 protein and/or its Ant2 gene.