We made use of a homologous cell-free mitochondrial protein import system derived from the yeast Saccharomyces cerevisiae to investigate the coupling of protein synthesis and import. Mitochondrial precursor proteins were synthesized in a yeast lysate either in the presence or absence of isolated yeast mitochondria. We were, therefore, able to analyze protein import into mitochondria either in a...

Protein import into chloroplasts is an energy-requiring process mediated by a proteinaceous import apparatus. Although previous work has shown that low levels of ATP or GTP can support precursor binding, the role of GTP during the import process remains unclear. Specifically, it is unknown whether GTP plays a separate role from ATP during the early stages of protein import and whether GTP has a...

The Saccharomyces cerevisiae gene, RNA1, encodes a protein with extensive homology to the mammalian Ran/TC4 GTPase activating protein. Using indirect immunofluorescence microscopy, we have demonstrated that rna1-1 mutant cells are defective in nuclear import of several proteins. The same result is obtained when nuclear import is examined in living cells using a nuclear protein fused to the natu...

The nucleus-encoded mitochondria-targeted proteins, multiple organellar RNA editing factors (MORF3, MORF5, and MORF6), interact with Arabidopsis (Arabidopsis thaliana) PURPLE ACID PHOSPHATASE2 (AtPAP2) located on the chloroplast and mitochondrial outer membranes in a presequence-dependent manner. Phosphorylation of the presequence of the precursor MORF3 (pMORF3) by endogenous kinases in wheat g...

Metabolite carrier proteins of the mitochondrial inner membrane share homology in their transmembrane domains, which also carries their targeting information. In addition, some carriers have cleavable presequences which are not essential for targeting, but have some other function before import. The cytosolic chaperones Hsc70 (heat-shock cognate 70) and Hsp90 (heat-shock protein 90) complex wit...

rice comes second after wheat in iran`s food consumption economy. however iran is one of the greatest rice importer countries all over the world because of its rising population and recent growth in gdp. this paper presents an analysis of cointegration test between rice import and it`s economic factors over the period 1990-2011, employing engle-granger model. at first, dickey-fuller test shows ...

rice comes second after wheat in iran`s food consumption economy. however iran is one of the greatest rice importer countries all over the world because of its rising population and recent growth in gdp. this paper presents an analysis of cointegration test between rice import and it`s economic factors over the period 1990-2011, employing engle-granger model. at first, dickey-fuller test shows ...

uclear import is slowed by too much of a good thing. So says a new systems model of nuclear import from Riddick and Macara (page 1027), which predicts that high levels of the cargo carrier Importin-␤ or the RanGEF RCC1 inhibit import. With its simple nucleus-versus-cytoplasm architecture, import is a good candidate for systems analysis. Most of the components have been identified, and biochemic...

Kinetic competition experiments have demonstrated that at least some factors required for the nuclear import of proteins and U snRNPs are distinct. Both import processes require energy, and in the case of protein import, the energy requirement is known to be at least partly met by GTP hydrolysis by the Ran GTPase. We have compared the effects of nonhydrolyzable GTP analogues and two mutant Ran ...

Nucleocytoplasmic trafficking pathways and the status of nuclear pore complex (NPC) components were examined in cells infected with rhinovirus type 14. A variety of shuttling and nonshuttling nuclear proteins, using multiple nuclear import pathways, accumulated in the cytoplasm of cells infected with rhinovirus. An in vitro nuclear import assay with semipermeabilized infected cells confirmed th...