IRA2, a second gene of Saccharomyces cerevisiae that encodes a protein with a domain homologous to mammalian ras GTPase-activating protein.

Tanaka, Katsuyuki; Nakafuku, Masato; Tamanoi, Fuyuhiko; Kaziro, Yoshito; Matsumoto, Kunihiro; Toh‐e, Akio

doi:10.1128/mcb.10.8.4303

Cited by 289 publications

(225 citation statements)

References 37 publications

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“…To overproduce mutant Pho85 proteins driven by the TDH3 promoter in a YEp vector, a derivative of plasmid pKT10 (Tanaka et al 1990) lacking a HindIII site was digested with EcoRI and KpnI to remove an ATG sequence. The plasmid was self-ligated and then cut with XhoI and SalI, and to the gap, a fragment with corresponding ends carrying the PHO85 coding region without the intron (Fujino et al 1994) was inserted to generate TOp61 plasmid, which was then cut with HindIII and KpnI to replace the wild-type sequence with a mutant sequence.…”

Section: Construction Of Pho85 Mutantsmentioning

confidence: 99%

The Pho85 kinase, a member of the yeast cyclin‐ dependent kinase (Cdk) family, has a regulation mechanism different from Cdks functioning throughout the cell cycle

et al. 1999

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Background: The PHO85 gene is a negative regulator of the PHO system in the yeast Saccharomyces cerevisiae and encodes a protein kinase (Pho85p) which is highly homologous to the Cdc28 kinase (Cdc28p). Although the two kinases share a 51% identity and their functional domains are well conserved, PHO85 fails to replace CDC28. Pho85p forms complexes with G 1 -cyclin homologues, including Pcl1p, Pcl2p and Pcl9p, and is thought to be involved in the cell-cycle regulation at G 1 and the end of M. By analysing the genetic and biochemical properties of Pho85p, we studied whether the regulation of Pho85p activity is similar to other cyclin-dependent kinases (Cdks) directly involved in cell cycle regulation.

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Section: Construction Of Pho85 Mutantsmentioning

confidence: 99%

The Pho85 kinase, a member of the yeast cyclin‐ dependent kinase (Cdk) family, has a regulation mechanism different from Cdks functioning throughout the cell cycle

et al. 1999

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“…To express AtAPG proteins in yeast, each AtAPG gene was inserted under the GAP promoter of yeast expression vector pKT10 (Tanaka et al, 1990). Yeast strains were grown in standard rich medium (yeast peptone dextrose) or starvation medium as described previously .…”

Section: Complementation Test Of Yeast Apg Mutants With Atapg Genesmentioning

confidence: 99%

Leaf Senescence and Starvation-Induced Chlorosis Are Accelerated by the Disruption of an Arabidopsis Autophagy Gene

et al. 2002

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Autophagy is an intracellular process for vacuolar bulk degradation of cytoplasmic components. The molecular machinery responsible for yeast and mammalian autophagy has recently begun to be elucidated at the cellular level, but the role that autophagy plays at the organismal level has yet to be determined. In this study, a genome-wide search revealed significant conservation between yeast and plant autophagy genes. Twenty-five plant genes that are homologous to 12 yeast genes essential for autophagy were discovered. We identified an Arabidopsis mutant carrying a T-DNA insertion within AtAPG9, which is the only ortholog of yeast Apg9 in Arabidopsis (atapg9-1). AtAPG9 is transcribed in every wild-type organ tested but not in the atapg9-1 mutant. Under nitrogen or carbon-starvation conditions, chlorosis was observed earlier in atapg9-1 cotyledons and rosette leaves compared with wild-type plants. Furthermore, atapg9-1 exhibited a reduction in seed set when nitrogen starved. Even under nutrient growth conditions, bolting and natural leaf senescence were accelerated in atapg9-1 plants. Senescence-associated genes SEN1 and YSL4 were up-regulated in atapg9-1 before induction of senescence, unlike in wild type. All of these phenotypes were complemented by the expression of wild-type AtAPG9 in atapg9-1 plants. These results imply that autophagy is required for maintenance of the cellular viability under nutrient-limited conditions and for efficient nutrient use as a whole plant.Protein degradation is an important process in almost every facet of plant physiology and development. In plants, three major degradation pathways have been described: the ubiquitin-dependent pathway and the chloroplast and the vacuolar degradation pathways (for review, see Vierstra, 1996). Among these pathways, vacuolar degradation is assumed to be involved in bulk protein degradation by virtue of the resident proteases in the vacuole. Two types of vacuoles have been described in plants: the storage vacuole and the lytic central vacuole (for review, see Marty, 1999). However, there may be additional vacuole types that await discovery. Protein storage vacuoles are often found in seed tissues and accumulate proteins that are mobilized and used as the main nutrient resource for germination. Most cells in vegetative tissues have a large central vacuole, containing a wide range of proteases in an acidic environment. Substrate proteins must be transported and sequestered into this vacuole for degradation.Autophagy, a ubiquitous eukaryotic process, is responsible for this sequestration. Two types of autophagy have been described, namely macroautophagy and microautophagy (for review, see Klionsky and Ohsumi, 1999). In yeast macroautophagy, a portion of the cytoplasm is first enclosed by a doublemembrane structure, the autophagosome. The outer membrane of the autophagosome then fuses to the vacuolar membrane, so that its inner membrane structure, the autophagic body, is delivered into the vacuolar lumen. The contents of the autophagic body are then digest...

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“…The NF1 gene contains a region, the NF1 GAP related domain (GRD), which is similar in function and sequence to catalytic domains of the mammalian GTPase activating protein (GAP) (Xu et al, 1990) and to yeast IRA proteins (Tanaka et al, 1990), both of which mediate the hydrolysis of ras-bound GTP which is an active form of ras to an inactive GDP-bound form (McCormick et al, 1988;Vogel et al, 1988). Schwannoma cell lines expressing low levels of NF1 protein product contain abnormally high levels of active GTP-bound ras.…”

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confidence: 99%

Differential expression of NF1 type I and type II isoforms in sporadic borderline and invasive epithelial ovarian tumors

Iyengar

Lau

et al. 1999

Oncogene

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The NF1 gene, a putative tumor suppressor gene, contains a GAP related domain (GRD) which accelerates hydrolysis of ras-bound GTP to GDP, thereby converting the ras oncogene from its active to inactive form. Two forms of the NF1 GRD transcript (Type I and Type II) are di erentially expressed in neuroectodermal tumor tissue relative to di erentiated neural cells, and in gastric cancer cell lines relative to normal stomach mucosa. We measured relative expression of NF1 Type II and Type I isoforms in cultured normal and malignant human ovarian surface epithelial cells(HOSE) and in invasive and borderline ovarian tumor tissue. We demonstrated an 11-fold increase in Type II: Type I ratio in 7 HOSE cultures relative to eight ovarian cancer cell lines. Our ®ndings indicate a signi®cant decrease in Type II isoform expression and increase in Type I expression in ovarian cancer cells and tumor tissue relative to HOSE cells. We also demonstrate an increase in Type II: Type I ratio, and a decrease in cell proliferation rate in three ovarian cancer cell lines on treatment with retinoic acid. We propose that di erential expression of the NF1 Type I and Type II isoforms is related to cellular di erentiation in ovarian epithelial cancer and strategies based on alteration in NF1 isoform expression may have therapeutic potential in ovarian malignancies.Keywords: ovary; cancer; NF1; retinoic acid Ovarian cancer is the ®fth most common cancer and the fourth leading cause of cancer death among women in the United States. It is the leading cause of death by gynecologic malignancy. While much of our understanding of the genetic basis of ovarian cancer remains speculative, evidence indicates that development of ovarian tumors requires a series of genetic changes involving dominant oncogenes, mismatch repair genes, and a large number of tumor suppressor genes (Cliby et al

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IRA2, a second gene of Saccharomyces cerevisiae that encodes a protein with a domain homologous to mammalian ras GTPase-activating protein.

Cited by 289 publications

References 37 publications

The Pho85 kinase, a member of the yeast cyclin‐ dependent kinase (Cdk) family, has a regulation mechanism different from Cdks functioning throughout the cell cycle

The Pho85 kinase, a member of the yeast cyclin‐ dependent kinase (Cdk) family, has a regulation mechanism different from Cdks functioning throughout the cell cycle

Leaf Senescence and Starvation-Induced Chlorosis Are Accelerated by the Disruption of an Arabidopsis Autophagy Gene

Differential expression of NF1 type I and type II isoforms in sporadic borderline and invasive epithelial ovarian tumors

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