PubMed Health⌕ Search

PubMed · 10073572

In yeast, upc2-1 confers a decrease in tolerance to LiCl and NaCl, which can be suppressed by the P-type ATPase encoded by ENA2.

Abstract

Wild-type yeast cells are unable to take up sterols from their growth media under aerobic conditions and are relatively resistant to monovalent cations. A yeast mutant (upc2-1) with a defect in the aerobic exclusion of sterols was found to have increased sensitivity to LiCl and NaCl. Although cation sensitivity has been reported for mutants that synthesize altered sterols, the mutant with upc2-1 continues to produce the normal sterol, ergosterol. The ENA2 gene was cloned on the basis of remediating the hypersensitivity to the monovalent cations.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

F W Leak, S Tove, L W Parks. 1999. In yeast, upc2-1 confers a decrease in tolerance to LiCl and NaCl, which can be suppressed by the P-type ATPase encoded by ENA2.. https://doi.org/10.1089/104454999315510

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Isolation and characterization of Plasmodium falciparum UAP56 homolog: evidence for the coupling of RNA binding and splicing activity by site-directed mutations.

UAP56 (U2AF65 associated protein) is a member of the DEAD-box helicase family. Helicases are essential enzymes generally involved in the metabolism of nucleic acids. The gene encoding a member of DEAD-box family was cloned and characterized from the human malaria parasite Plasmodium falciparum. PfU52 is homologous to UAP56 and contains the RNA-dependent ATPase, RNA helicase and RNA binding activities. Using the parasite extract we report that PfU52 is involved in splicing reaction. Site-directed mutagenesis studies indicate that the conserved residues glycine 181, isoleucine 182 and arginine 206 are involved in RNA binding and this activity is required for the enzymatic activities of PfU52. PfU52 is expressed in all the intraerythrocytic developmental stages of the parasite. In the present study we have reported the detailed characterization of PfU52 from P. falciparum and these results advance the knowledge regarding the function of UAP56 in general.

Adenosine Triphosphatases↗

Targeting of aminopeptidase I to the yeast vacuole is mediated by Ssa1p, a cytosolic member of the 70-kDa stress protein family.

The two cytosolic members of the highly conserved 70-kDa stress protein family, Ssa1p and Ssa2p, were specifically retained by the prepro-NH(2) extension of the vacuolar aminopeptidase I precursor (pAPI) conjugated to agarose (Sulfolink). A temperature-sensitive mutant strain a1(ts)a234 (ssa1(ts) ssa2 ssa3 ssa4), when incubated at the restrictive temperature, was able to assemble the API precursor into dodecamers, but failed to pack pAPI into vesicles and to convert it into mature API (mAPI), a process that occurs in the vacuole. Altogether these results indicate that Ssa1p mediates the targeting of pAPI to the vacuole.

Adenosine Triphosphatases↗

Domain analysis of an archaeal RadA protein for the strand exchange activity.

Archaeal RadA, like eukaryotic Rad51 and bacterial RecA, promotes strand exchange between DNA strands with homologous sequences in vitro and is believed to participate in the homologous recombination in cells. The amino acid sequences of the archaeal RadA proteins are more similar to the eukaryotic Rad51s rather than the bacterial RecAs, and the N-terminal region containing domain I is conserved among the RadA and Rad51 proteins but is absent from RecA. To understand the structure-function relationship of RadA, we divided the RadA protein from Pyrococcus furiosus into two parts, the N-terminal one-third (RadA-n) and the residual C-terminal two-thirds (RadA-c), the latter of which contains the central core domain (domain II) of the RecA/Rad51 family proteins. RadA-c had the DNA-dependent ATPase activity and the strand exchange activity by itself, although much weaker (10%) than that of the intact RadA. These activities of RadA-c were restored to 60% of those of RadA by addition of RadA-n, indicating that the proper active structure of RadA was reconstituted in vitro. These results suggest that the basic activities of the RecA/Rad51 family proteins for homologous recombination are derived from domain II, and the N-terminal region may help to enhance the catalytic efficiencies.

Adenosine Triphosphatases↗