BACKGROUND To identify novel proteins involved in multidrug resistance in chronic myeloid leukemia (CML). MATERIALS AND METHODS Comparative proteomics was used to screen multidrug resistance-related proteins from K562 and K562/A02; the differently expressed proteins were further confirmed by western blot and real-time PCR. short hairpin RNA (shRNA) assay was applied to determine the relations...

Function of the cyanide-sensitive mitochondrial electron transport system was required for germination of the Zea mays embryo. Respiration of the standard electron transport system (rather than the alternate oxidase) began immediately upon initiation of imbibition. This respiration depended upon cytochrome c oxidase and ATPase that were conserved in an active form in the quiescent embryo rather...

The precursor of porin, a mitochondrial outer membrane protein, competes for the import of precursors destined for the three other mitochondrial compartments, including the Fe/S protein of the bc1-complex (intermembrane space), the ADP/ATP carrier (inner membrane), subunit 9 of the F0-ATPase (inner membrane), and subunit beta of the F1-ATPase (matrix). Competition occurs at the level of a commo...

Previously we have shown, using two-dimensional electrophoresis, that mitochondrial ATP synthase (F(o)F(1)-ATPase) beta-subunit is the 55-kDa protein increased in cold-acclimated carp Cyprinus carpio (Kikuchi K, Itoi S, and Watabe S. Fisheries Sci 65: 629-636, 1999). To clarify the coordinate expression in various subunits of carp F(o)F(1)-ATPase with temperature acclimation, we examined the di...

A complete inactivation is observed after a 3 min pre-incubation at 70 degrees C with mitochondrial F0F1-ATPase complex depleted of the ATPase natural inhibitor protein (ammonium-Sephadex submitochondrial particles) and activated MgATP-submitochondrial particles (particles that after a 4 h-pre-incubation at 42 degrees C released the endogenous inhibitor protein). However, latent MgATP-submitoch...

Dysfunction of mitochondrial ATPase (F1F(o)-ATP synthase) due to missense mutations in ATP6 [mtDNA (mitochondrial DNA)-encoded subunit a] is a frequent cause of severe mitochondrial encephalomyopathies. We have investigated a rare mtDNA mutation, i.e. a 2 bp deletion of TA at positions 9205 and 9206 (9205DeltaTA), which affects the STOP codon of the ATP6 gene and the cleavage site between the R...

A triazine-based combinatorial library of small molecules was screened in zebrafish to identify compounds that produced interesting phenotypes. One compound (of 1536 screened) induced a dramatic increase in the pigmentation of early stage zebrafish embryos. This compound, PPA, was also found to increase pigmentation in cultured mammalian melanocytes. The cellular target was identified as the mi...

A heat-stable protein has been detected in Saccharomyces cerevisiae which inhibits mitochondrial ATPase activity. The protein inhibitor has been isolated from extracts prepared by brief heat treatment of unbroken cell suspensions. The isolated inhibitor is a small basic protein (molecular weight close to 7000, isoelectric proint 9.05) devoid of tryptophan, tyrosine, and cysteine as well as prol...

Hypoxia impairs alveolar fluid reabsorption by promoting Na,K-ATPase endocytosis, from the plasma membrane of alveolar epithelial cells. The present study was designed to determine whether hypoxia induces Na,K-ATPase endocytosis via reactive oxygen species (ROS)-mediated RhoA activation. In A549 cells, RhoA activation occurred within 15 minutes of cells exposure to hypoxia. This activation was ...