title: Effect of the CRAC Peptide, VLNYYVW, on mPTP Opening in Rat Brain and Liver Mitochondria.
abstract: The translocator protein (TSPO; 18 kDa) is a high-affinity cholesterol-binding protein located in the outer membrane of mitochondria. A domain in the C-terminus of TSPO was characterized as the cholesterol recognition/interaction amino acid consensus (CRAC). The ability of the CRAC domain to bind to cholesterol led us to hypothesize that this peptide may participate in the regulation of mitochondrial membrane permeability. Herein, we report the effect of the synthetic CRAC peptide, VLNYYVW, on mitochondrial permeability transition pore (mPTP) opening. It was found that the CRAC peptide alone prevents the mPTP from opening, as well as the release of apoptotic factors (cytochrome c, AIF, and EndoG) in rat brain mitochondria (RBM). Co-incubation of CRAC, together with the TSPO drug ligand, PK 11195, resulted in the acceleration of mPTP opening and in the increase of apoptotic factor release. VLNYYVW did not induce swelling in rat liver mitochondria (RLM). 3,17,19-androsten-5-triol (19-Atriol; an inhibitor of the cholesterol-binding activity of the CRAC peptide) alone and in combination with the peptide was able to stimulate RLM swelling, which was Ca2+- and CsA-sensitive. Additionally, a combination of 19-Atriol with 100 nM PK 11195 or with 100 µM PK 11195 displayed the opposite effect: namely, the addition of 19-Atriol with 100 µM PK 11195 in a suspension of RLM suppressed the Ca2+-induced swelling of RLM by 40%, while the presence of 100 nM PK 11195 with 19-Atriol enhanced the swelling of RLM by 60%. Taken together, these data suggest the participation of the TSPO's CRAC domain in the regulation of permeability transition.
authors.affiliation: Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region 142290, Russia. tamara.azarashvili@gmail.com.
authors.forename: Tamara
authors.initials: T
authors.lastname: Azarashvili
authors.affiliation: Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region 142290, Russia. krestinina@rambler.ru.
authors.forename: Olga
authors.initials: O
authors.lastname: Krestinina
authors.affiliation: Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region 142290, Russia. byul@rambler.ru.
authors.forename: Yulia
authors.initials: Y
authors.lastname: Baburina
authors.affiliation: Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region 142290, Russia. odinokova@rambler.ru.
authors.forename: Irina
authors.initials: I
authors.lastname: Odinokova
authors.affiliation: Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region 142290, Russia. akatov.vladimir@gmail.com.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Akatov
authors.affiliation: Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Institutskaya Str., Pushchino, Moscow Region 142290, Russia. ipbeletsky@gmail.com.
authors.forename: Igor
authors.initials: I
authors.lastname: Beletsky
authors.affiliation: Departments of Drug Discovery & Biomedical Sciences and Biochemistry & Molecular Biology, Medical University of South Carolina, DD504 Drug Discovery Bldg., 70 President St., MSC 140, Charleston, SC 29425, USA. JJLemasters@musc.edu.
authors.forename: John
authors.initials: J
authors.lastname: Lemasters
authors.affiliation: The Research Institute of the McGill University Health Center, and Departments of Medicine, Biochemistry, Pharmacology and Therapeutics, McGill University, 2155 Guy Street, Montreal, QC H3H 2R9, Canada. vassilios.papadopoulos@mcgill.ca.
authors.forename: Vassilios
authors.initials: V
authors.lastname: Papadopoulos
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D051033:Apoptosis Inducing Factor / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D007546:Isoquinolines / Q000494:pharmacology; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins / Q000378:metabolism*; D000083162:Mitochondrial Permeability Transition Pore; D008933:Mitochondrial Swelling / Q000187:drug effects; D009842:Oligopeptides / Q000737:chemistry* / Q000494:pharmacology*; D010455:Peptides / Q000737:chemistry* / Q000494:pharmacology*; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000378:metabolism
chemical_list: D051033:Apoptosis Inducing Factor; D002352:Carrier Proteins; D007546:Isoquinolines; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D009842:Oligopeptides; D010455:Peptides; D011963:Receptors, GABA-A; C000616955:valyl-leucyl-asparagyl-tyrosyl-tyrosyl-valyl-tryptophan; C069997:Tspo protein, rat; D045304:Cytochromes c; D002118:Calcium; C037850:PK 11195
keywords: cholesterol recognition/interaction amino acid consensus (CRAC); mitochondria; permeability transition; translocator protein (TSPO)