von Stockum Sophia, Giorgio Valentina, Trevisan Elena, Lippe Giovanna, Glick Gary D, Forte Michael A, Da-Rè Caterina, Checchetto Vanessa, Mazzotta Gabriella, Costa Rodolfo, Szabò Ildikò, Bernardi Paolo
From the Departments of Biomedical Sciences and.
the Department of Food Science, University of Udine, I-33100 Udine, Italy.
J Biol Chem. 2015 Feb 20;290(8):4537-4544. doi: 10.1074/jbc.C114.629766. Epub 2014 Dec 30.
Mitochondria of Drosophila melanogaster undergo Ca(2+)-induced Ca(2+) release through a putative channel (mCrC) that has several regulatory features of the permeability transition pore (PTP). The PTP is an inner membrane channel that forms from F-ATPase, possessing a conductance of 500 picosiemens (pS) in mammals and of 300 pS in yeast. In contrast to the PTP, the mCrC of Drosophila is not permeable to sucrose and appears to be selective for Ca(2+) and H(+). We show (i) that like the PTP, the mCrC is affected by the sense of rotation of F-ATPase, by Bz-423, and by Mg(2+)/ADP; (ii) that expression of human cyclophilin D in mitochondria of Drosophila S2R(+) cells sensitizes the mCrC to Ca(2+) but does not increase its apparent size; and (iii) that purified dimers of D. melanogaster F-ATPase reconstituted into lipid bilayers form 53-pS channels activated by Ca(2+) and thiol oxidants and inhibited by Mg(2+)/γ-imino ATP. These findings indicate that the mCrC is the PTP of D. melanogaster and that the signature conductance of F-ATPase channels depends on unique structural features that may underscore specific roles in different species.
黑腹果蝇的线粒体通过一个假定的通道(mCrC)经历钙诱导的钙释放,该通道具有通透性转换孔(PTP)的几个调节特征。PTP是一种由F-ATP酶形成的内膜通道,在哺乳动物中的电导为500皮西门子(pS),在酵母中的电导为300 pS。与PTP不同,果蝇的mCrC对蔗糖不渗透,似乎对Ca(2+)和H(+)具有选择性。我们发现:(i)与PTP一样,mCrC受F-ATP酶的旋转方向、Bz-423以及Mg(2+)/ADP的影响;(ii)人亲环蛋白D在果蝇S2R(+)细胞线粒体中的表达使mCrC对Ca(2+)敏感,但不会增加其表观大小;(iii)重组到脂质双层中的纯化黑腹果蝇F-ATP酶二聚体形成53-pS的通道,该通道被Ca(2+)和硫醇氧化剂激活,并被Mg(2+)/γ-亚氨基ATP抑制。这些发现表明,mCrC是黑腹果蝇的PTP,并且F-ATP酶通道的标志性电导取决于独特的结构特征,这些特征可能突出了其在不同物种中的特定作用。