title: Knockdown of F1 epsilon subunit decreases mitochondrial content of ATP synthase and leads to accumulation of subunit c.
abstract: The subunit epsilon of mitochondrial ATP synthase is the only F1 subunit without a homolog in bacteria and chloroplasts and represents the least characterized F1 subunit of the mammalian enzyme. Silencing of the ATP5E gene in HEK293 cells resulted in downregulation of the activity and content of the mitochondrial ATP synthase complex and of ADP-stimulated respiration to approximately 40% of the control. The decreased content of the epsilon subunit was paralleled by a decrease in the F1 subunits alpha and beta and in the Fo subunits a and d while the content of the subunit c was not affected. The subunit c was present in the full-size ATP synthase complex and in subcomplexes of 200-400 kDa that neither contained the F1 subunits, nor the Fo subunits. The results indicate that the epsilon subunit is essential for the assembly of F1 and plays an important role in the incorporation of the hydrophobic subunit c into the F1-c oligomer rotor of the mitochondrial ATP synthase complex.
authors.affiliation: Department of Bioenergetics, Institute of Physiology and Centre for Applied Genomics, Academy of Sciences of the Czech Republic, 142 20 Prague.
authors.forename: Vendula
authors.initials: V
authors.lastname: Havlícková
authors.forename: Vilma
authors.initials: V
authors.lastname: Kaplanová
authors.forename: Hana
authors.initials: H
authors.lastname: Nůsková
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Drahota
authors.forename: Josef
authors.initials: J
authors.lastname: Houstek
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis; D001483:Base Sequence; D055785:Gene Knockdown Techniques; D057809:HEK293 Cells; D006801:Humans; D008928:Mitochondria / Q000201:enzymology*; D025261:Mitochondrial Proton-Translocating ATPases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010085:Oxidative Phosphorylation; D021122:Protein Subunits; D011506:Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D000097795:ATPase Inhibitory Protein
chemical_list: D000255:Adenosine Triphosphate; D025261:Mitochondrial Proton-Translocating ATPases; D021122:Protein Subunits; D011506:Proteins; D034741:RNA, Small Interfering; D000097795:ATPase Inhibitory Protein