A novel FK506- and rapamycin-binding protein (FPR3 gene product) in the yeast Saccharomyces cerevisiae is a proline rotamase localized to the nucleolus.

Abstract

Abbreviations used in this paper:CsA, cyclosporin A; FKBP, FKS06-binding protein; Gal, 2% galactose supplemented with 0.2% sucrose; Glc, 2 % glucose; GST, Schistosomajaponicura glutathione S-transferase; HSE, heat shock response element; Hsp, heat shock protein; PPIases, peptidylprolyl-cis, trans-isomerases. in protein folding and protein assembly events in vivo (Parsell and Lindquist, 1993) because in vitro these enzymes catalyze interconversion of the cis and trans isomers of the bond between the carboxyl group of the preceding amino acid and the imino nitrogen of proline in peptide and protein substrates (Kofron et al., 1991;Stein, 1991). It was discovered several years ago that there are two separate types of PPIases. This realization was made possible by investigations into the molecular mode of action of antibiotics that act as immunosuppressants in humans. These drugs effectively block the specific signal transduction pathways required for activation and proliferation of T lymphocytes (for review see Schreiber et al., 1993).The first PPIase isolated (Fischer et al., 1984) was shown to be the intracellular receptor for an immunosuppressant, cyclosporin A (CsA); and hence, a member of this class of PPIase is called a cyclophilin (Fischer et al., 1989; Taka-

Two novel targets of the MAP kinase Kss1 are negative regulators of invasive growth in the yeast Saccharomyces cerevisiae.

“…4). The apparent size of Digl based on gel mobility is significantly larger than its calculated molecular weight, which is a frequently observed anomaly for highly charged and proline-rich proteins (for example, see Benton et al 1994). Neither the steady-state level nor the electrophoretic mobility of Digl were detectably altered by prior pheromone treatment of the cells (data not shown).…”

“…Plasmids encoding fusions detectably larger than the GAD domain itself were extracted from the yeast cells and recovered by transformation in E. coli. Specificity for interaction with Kss 1 was confirmed by failure of the fusions expressed by the recovered library plasmids to give a positive signal when cotransformed with a vector-only control, or with GAD fusions to Raf (Van Aelst et al 1993) (gift of M. Wigler, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY}; Rb (Durfee et al 1993} {gift of T. Durfee, University of California, Berkeley, CA); Fpr3 (Benton et al 1994) (gift of N. Dhillon, this laboratory); and Rad3 (Bardwell et al 1994a). The nucleotide sequences of the inserts in these plasmids were partially determined using primer Ga14-850 (5'-GGAATCACTACAGGGATG-3') and compared with the S. cerevisiae genome data base using the BLAST-N search algorithm (Altschul et al 1990).…”

Large‐scale screening of intracellular protein localization in living fission yeast cells by the use of a GFP‐fusion genomic DNA library

“…2C for TC37, TA78 and Z031. One of them, TC37, is homologous to FK506-and rapamycin-binding protein (FKBP); two kinds of FKBP have been shown to localize to the nucleolus in S. cerevisiae (Benton et al 1994;Shan et al 1994).…”

The in vivo tyrosine phosphorylation level of yeast immunophilin Fpr3 is influenced by the LMW-PTP Ltp1

“…The plasmid pyFpr3, used to obtain the overexpressing Fpr3 strain, is a gift from Thorner and co-workers [25].…”

“…Even if fpr3 null mutations had no discernible phenotype [24], cells might be more sensitive to stress conditions accumulating higher level of misfolded proteins and aggregated unassembled proteins than wild-type cells, which might act as a signal to induce stress response. Localization of Fpr3 in the nucleolus suggests possible roles of this PPIase in the folding of ribosomal proteins, in the assembly of pre-ribosomes or in the export of ribosomes to the cytoplasm [25]. Furthermore, like other nucleolar proteins, it is phosphorylated in vivo.…”