Senoo Nanami, Chinthapalli Dinesh K, Baile Matthew G, Golla Vinaya K, Saha Bodhisattwa, Ogunbona Oluwaseun B, Saba James A, Munteanu Teona, Valdez Yllka, Whited Kevin, Chorev Dror, Alder Nathan N, May Eric R, Robinson Carol V, Claypool Steven M
Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Mitochondrial Phospholipid Research Center, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
bioRxiv. 2023 May 6:2023.05.05.539595. doi: 10.1101/2023.05.05.539595.
The mitochondrial phospholipid cardiolipin (CL) promotes bioenergetics via oxidative phosphorylation (OXPHOS). Three tightly bound CLs are evolutionarily conserved in the ADP/ATP carrier (AAC in yeast; adenine nucleotide translocator, ANT in mammals) which resides in the inner mitochondrial membrane and exchanges ADP and ATP to enable OXPHOS. Here, we investigated the role of these buried CLs in the carrier using yeast Aac2 as a model. We introduced negatively charged mutations into each CL-binding site of Aac2 to disrupt the CL interactions via electrostatic repulsion. While all mutations disturbing the CL-protein interaction destabilized Aac2 monomeric structure, transport activity was impaired in a pocket-specific manner. Finally, we determined that a disease-associated missense mutation in one CL-binding site in ANT1 compromised its structure and transport activity, resulting in OXPHOS defects. Our findings highlight the conserved significance of CL in AAC/ANT structure and function, directly tied to specific lipid-protein interactions.
线粒体磷脂心磷脂（CL）通过氧化磷酸化（OXPHOS）促进生物能量学。在位于线粒体内膜的ADP/ATP载体（酵母中的AAC；哺乳动物中的腺嘌呤核苷酸转运体，ANT）中，有三个紧密结合的CL在进化上是保守的，该载体交换ADP和ATP以实现OXPHOS。在这里，我们以酵母Aac2为模型研究了这些埋藏的CL在载体中的作用。我们在Aac2的每个CL结合位点引入带负电荷的突变，通过静电排斥破坏CL相互作用。虽然所有干扰CL-蛋白质相互作用的突变都使Aac2单体结构不稳定，但转运活性以口袋特异性方式受损。最后，我们确定ANT1中一个CL结合位点的疾病相关错义突变损害了其结构和转运活性，导致OXPHOS缺陷。我们的发现突出了CL在AAC/ANT结构和功能中的保守意义，这与特定的脂-蛋白质相互作用直接相关。
