Yeast NPI46 encodes a novel prolyl cis-trans isomerase that is located in the nucleolus.

Shan, Xiaoyin; Xue, Zhixiong; Melese, Teri

doi:10.1083/jcb.126.4.853

Cited by 62 publications

(48 citation statements)

References 41 publications

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“…The polypeptide, termed Nopp52, exhibits a highly modular domain structure with alternating acidic/basic repeats distinguishing its amino-terminal half. A similar organization of alternating acidic/basic stretches has also been described in many nucleolar proteins including nucleolin, NSR1, NpI46, Noppl40, and B23/No38 (Dingwall et al, 1987;Lapeyre et al, 1987;Lee et al, 1991;Meier and Blobel, 1992;Shan et al, 1994). Many of this class of polypeptides, including Nopp52, have aberrantly slow mobility in SDS gels and are phosphorylated by CKII.…”

Section: Discussionmentioning

confidence: 93%

An abundant nucleolar phosphoprotein is associated with ribosomal DNA in Tetrahymena macronuclei.

McGrath

Smothers

Dadd

et al. 1997

MBoC

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Section: Discussionmentioning

confidence: 93%

An abundant nucleolar phosphoprotein is associated with ribosomal DNA in Tetrahymena macronuclei.

McGrath

Smothers

Dadd

et al. 1997

MBoC

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“…When this domain is expressed independently, it is retained in the cytoplasm and restores FK506 and rapamycin sensitivity in fpr1⌬ strains. The amino-terminal two-thirds of Fpr3 contains striking regions of acidic and basic residues and is responsible for localization of Fpr3 in the nucleolus (18,34,35). This portion of Fpr3 exhibits some sequence similarity to nucleolin, a major nucleolar protein thought to be involved in ribosome assembly and shuttling of RNA or proteins through nuclear pores (for review, see Ref.…”

Section: Discussionmentioning

confidence: 99%

The Yeast Immunophilin Fpr3 Is a Physiological Substrate of the Tyrosine-specific Phosphoprotein Phosphatase Ptp1

Wilson

Benton

Zhou

et al. 1995

Journal of Biological Chemistry

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The tyrosine-specific phosphoprotein phosphatase encoded by the Saccharomyces cerevisiae PTP1 gene dephosphorylates artificial substrates in vitro, but little is known about its functions and substrates in vivo. The presence of Ptp1 resulted in dephosphorylation of multiple tyrosine-phosphorylated proteins in yeast expressing a heterologous tyrosine-specific protein kinase, indicating that Ptp1 can dephosphorylate a broad range of substrates in vivo. Correspondingly, several proteins phosphorylated at tyrosine by endogenous protein kinases exhibited a marked increase in tyrosine phosphorylation in ptp1 mutant cells. One of these phosphotyrosyl proteins (p70) was also dephosphorylated in vitro when incubated with recombinant Ptp1. p70 was purified to homogeneity; analysis of four tryptic peptides revealed that p70 is identical to the recently described FPR3 gene product, a nucleolarly localized proline rotamase of the FK506-and rapamycin-binding family. The identity of p70 with Fpr3 was confirmed in the demonstration that the abundance of tyrosine-phosphorylated p70 in ptp1 mutants was strictly correlated with the level of FPR3 expression; immobilized phosphotyrosyl Fpr3 was directly dephosphorylated by recombinant Ptp1. Site-directed mutagenesis demonstrated that the site of tyrosine phosphorylation is Tyr-184, which resides within the nucleolin-like amino-terminal domain of Fpr3. Protein kinase activities from yeast cell extracts can bind to and phosphorylate the immobilized aminoterminal domain of Fpr3 on serine, threonine, and tyrosine. Fpr3 represents the first phosphotyrosyl protein identified in S. cerevisiae that is not itself a protein kinase and is as yet the only known physiological substrate of Ptp1.Phosphotyrosine-specific phosphoprotein phosphatases (PTPs) 1 have been identified in many evolutionarily divergent eukaryotes. These enzymes form a distinct superfamily and are unrelated in sequence to serine/threonine-specific phosphoprotein phosphatases (for reviews, see Refs.

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“…From the screen, we identified a plasmid containing the full ORF of FPR3 along with its upstream and downstream sequences, which was able to partially rescue the heat sensitivity of a ⌬ynm3 strain. FPR3 encodes a PPIase localized to the nucleolus of the budding yeast (Shan et al, 1994). We cloned the FPR3 ORF into a single copy vector under the control of the MET25 promoter.…”

Section: A Genetic Screen Identified Fpr3 As a Suppressor Of The Heatmentioning

confidence: 99%

The Yeast HtrA Orthologue Ynm3 Is a Protease with Chaperone Activity that Aids Survival Under Heat Stress

Padmanabhan

Fichtner

Dickmanns

et al. 2009

MBoC

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Ynm3 is the only budding yeast protein possessing a combination of serine protease and postsynaptic density 95/disclarge/zona occludens domains, a defining feature of the high temperature requirement A (HtrA) protein family. The bacterial HtrA/DegP is involved in protective stress response to aid survival at higher temperatures. The role of mammalian mitochondrial HtrA2/Omi in protein quality control is unclear, although loss of its protease activity results in susceptibility toward Parkinson's disease, in which mitochondrial dysfunction and impairment of protein folding and degradation are key pathogenetic features. We studied the role of the budding yeast HtrA, Ynm3, with respect to unfolding stresses. Similar to Escherichia coli DegP, we find that Ynm3 is a dual chaperone-protease. Its proteolytic activity is crucial for cell survival at higher temperature. Ynm3 also exhibits strong general chaperone activity, a novel finding for a eukaryotic HtrA member. We propose that the chaperone activity of Ynm3 may be important to improve the efficiency of proteolysis of aberrant proteins by averting the formation of nonproductive toxic aggregates and presenting them in a soluble state to its protease domain. Suppression studies with ⌬ynm3 led to the discovery of chaperone activity in a nucleolar peptidyl-prolyl cis-trans isomerase, Fpr3, which could partly relieve the heat sensitivity of ⌬ynm3.

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Yeast NPI46 encodes a novel prolyl cis-trans isomerase that is located in the nucleolus.

Cited by 62 publications

References 41 publications

An abundant nucleolar phosphoprotein is associated with ribosomal DNA in Tetrahymena macronuclei.

An abundant nucleolar phosphoprotein is associated with ribosomal DNA in Tetrahymena macronuclei.

The Yeast Immunophilin Fpr3 Is a Physiological Substrate of the Tyrosine-specific Phosphoprotein Phosphatase Ptp1

The Yeast HtrA Orthologue Ynm3 Is a Protease with Chaperone Activity that Aids Survival Under Heat Stress

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