A Missense Mutation in the RING Finger Motif of PEX2 Protein Disturbs the Import of Peroxisome Targeting Signal 1 (PTS1)-Containing Protein but Not the PTS2-Containing Protein

2000 ◽  
Vol 270 (3) ◽  
pp. 717-721 ◽  
Author(s):  
Yuan Huang ◽  
Ritsu Ito ◽  
Satoshi Miura ◽  
Takashi Hashimoto ◽  
Masaki Ito
Keyword(s):  
Missense Mutation ◽  
Ring Finger ◽  
Targeting Signal ◽  
Ring Finger Motif

Identification of PEX5p-related novel peroxisome-targeting signal 1 (PTS1)-binding proteins in mammals

2001 ◽  
Vol 357 (3) ◽  
pp. 635-646 ◽  
Author(s):  
Leen AMERY ◽  
Hideki SANO ◽  
Guy P. MANNAERTS ◽  
Jamie SNIDER ◽  
Jeroen van LOOY ◽  
...  
Keyword(s):  
Protein Import ◽  
Expressed Sequence Tag ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ring Finger ◽  
Ovary Cells ◽  
Targeting Signal ◽  
Related Proteins ◽  
The Brain

Based on peroxin protein 5 (Pex5p) homology searches in the expressed sequence tag database and sequencing of large full-length cDNA inserts, three novel and related human cDNAs were identified. The brain-derived cDNAs coded for two related proteins that differ only slightly at their N-terminus, and exhibit 39.8% identity to human PEX5p. The shorter liver-derived cDNA coded for the C-terminal tetratricopeptide repeat-containing domain of the brain cDNA-encoded proteins. Since these three proteins specifically bind to various C-terminal peroxisome-targeting signals in a manner indistinguishable from Pex5p and effectively compete with Pex5p in an in vitro peroxisome-targeting signal 1 (PTS1)-binding assay, we refer to them as ‘Pex5p-related proteins’ (Pex5Rp). In contrast to Pex5p, however, human PEX5Rp did not bind to Pex14p or to the RING finger motif of Pex12p, and could not restore PTS1 protein import in Pex5−/− mouse fibroblasts. Immunofluorescence analysis of epitope-tagged PEX5Rp in Chinese hamster ovary cells suggested an exclusively cytosolic localization. Northern-blot analysis showed that the PEX5R gene, which is localized to chromosome 3q26.2–3q27, is expressed preferentially in brain. Mouse PEX5Rp was also delineated. In addition, experimental evidence established that the closest-related yeast homologue, YMR018wp, did not bind PTS1. Based on its subcellular localization and binding properties, Pex5Rp may function as a regulator in an early step of the PTS1 protein import process.

scholarly journals Role of Baculovirus IE2 and Its RING Finger in Cell Cycle Arrest

1998 ◽  
Vol 72 (1) ◽  
pp. 684-692 ◽  
Author(s):  
Elena A. Prikhod’ko ◽  
Lois K. Miller
Keyword(s):  
Cell Cycle ◽  
Trichoplusia Ni ◽  
Helicoverpa Zea ◽  
Cell Cycle Progression ◽  
Ring Finger ◽  
Regulatory Activity ◽  
Cycle Progression ◽  
Dna Contents ◽  
Block Cell Cycle Progression ◽  
Ring Finger Motif

ABSTRACT The ie2 gene of Autographa californicanuclear polyhedrosis virus (AcMNPV) is known to transactivate transient expression from viral promoters in a host cell-specific manner. We report that transfection ofSpodoptera frugiperda (SF-21) cells with ie2was sufficient to arrest the cell cycle, resulting in the accumulation of enlarged cells with abnormally high DNA contents. By 72 h posttransfection, more than 50% of ie2-transfected cells had DNA contents greater than 4N. There was no evidence of mitotic spindle formation in these cells, and expression ofie2 appeared to block cell cycle progression in S phase. Several ie2 mutants were analyzed to further define the region of IE2 responsible for arresting the cell cycle. Analysis of these mutants showed that deletion of the RING finger motif eliminated the ability of IE2 to arrest the cell cycle but did not affect its ability to transactivate the ie1 promoter. Moreover, mutation of a single conserved cysteine (C251) of the RING finger motif abolished the ability of IE2 to block cell cycle progression but had no apparent effect on its trans-regulatory activity. In contrast, a mutant of IE2 containing a deletion of residues 94 to 173 was able to block cell division but lacked trans-regulatory activity. Thus, the ability of IE2 to arrest the cell cycle depended on the integrity of the RING finger motif and was distinct from and independent of its ability to trans-activate theie1 promoter. IE2 also arrested the division of cells derived from other insect species, Trichoplusia ni (TN-368 and BTI-TN-5B1-4) and Helicoverpa zea (Hz-AM1).

Cloning and chromosome mapping of the human Mel-18 gene which encodes a DNA-binding protein with a new ‘RING-finger’ motif

Gene ◽  
1993 ◽  
Vol 129 (2) ◽  
pp. 249-255 ◽  
Author(s):  
Atsushi Ishida ◽  
Hidefumi Asano ◽  
Masayuki Hasegawa ◽  
Haruhiko Koseki ◽  
Takao Ono ◽  
...  
Keyword(s):  
Dna Binding ◽  
Binding Protein ◽  
Ring Finger ◽  
Chromosome Mapping ◽  
Dna Binding Protein ◽  
Ring Finger Motif

scholarly journals APC2 Cullin Protein and APC11 RING Protein Comprise the Minimal Ubiquitin Ligase Module of the Anaphase-promoting Complex

2001 ◽  
Vol 12 (12) ◽  
pp. 3839-3851 ◽  
Author(s):  
Zhanyun Tang ◽  
Bing Li ◽  
Rajnish Bharadwaj ◽  
Haizhen Zhu ◽  
Engin Özkan ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Expression System ◽  
Ring Finger ◽  
Cyclin B1 ◽  
Anaphase Promoting Complex ◽  
Ubiquitin Ligase Activity ◽  
Cullin Protein ◽  
Canonical Ring ◽  
Heterodimeric Complex ◽  
Ring Finger Motif

In mitosis, the anaphase-promoting complex (APC) regulates the onset of sister-chromatid separation and exit from mitosis by mediating the ubiquitination and degradation of the securin protein and mitotic cyclins. With the use of a baculoviral expression system, we have reconstituted the ubiquitin ligase activity of human APC. In combination with Ubc4 or UbcH10, a heterodimeric complex of APC2 and APC11 is sufficient to catalyze the ubiquitination of human securin and cyclin B1. However, the minimal APC2/11 ubiquitin ligase module does not possess substrate specificity, because it also ubiquitinates the destruction box deletion mutants of securin and cyclin B1. Both APC11 and UbcH10 bind to the C-terminal cullin homology domain of APC2, whereas Ubc4 interacts with APC11 directly. Zn2+-binding and mutagenesis experiments indicate that APC11 binds Zn2+at a 1:3 M ratio. Unlike the two Zn2+ ions of the canonical RING-finger motif, the third Zn2+ ion of APC11 is not essential for its ligase activity. Surprisingly, with Ubc4 as the E2 enzyme, Zn2+ ions alone are sufficient to catalyze the ubiquitination of cyclin B1. Therefore, the Zn2+ ions of the RING finger family of ubiquitin ligases may be directly involved in catalysis.

scholarly journals Ubiquitination of the peroxisomal import receptor Pex5p

2004 ◽  
Vol 384 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Harald W. PLATTA ◽  
Wolfgang GIRZALSKY ◽  
Ralf ERDMANN
Keyword(s):  
Protein Import ◽  
Ring Finger ◽  
Proteasomal Degradation ◽  
Peroxisomal Membrane ◽  
Peroxisomal Biogenesis ◽  
Peroxisomal Targeting ◽  
Ubiquitin Conjugating Enzyme ◽  
Targeting Signal ◽  
Import Receptor ◽  
In Cells

Proteins harbouring a peroxisomal targeting signal of type 1 (PTS1) are recognized by the import receptor Pex5p in the cytosol which directs them to a docking and translocation complex at the peroxisomal membrane. We demonstrate the ubiquitination of Pex5p in cells lacking components of the peroxisomal AAA (ATPases associated with various cellular activities) or Pex4p–Pex22p complexes of the peroxisomal protein import machinery and in cells affected in proteasomal degradation. In cells lacking components of the Pex4p–Pex22p complex, mono-ubiquitinated Pex5p represents the major modification, while in cells lacking components of the AAA complex polyubiquitinated forms are most prominent. Ubiquitination of Pex5p is shown to take place exclusively at the peroxisomal membrane after the docking step, and requires the presence of the RING-finger peroxin Pex10p. Mono- and poly-ubiquitination are demonstrated to depend on the ubiquitin-conjugating enzyme Ubc4p, suggesting that the ubiquitinated forms of Pex5p are targeted for proteasomal degradation. Accumulation of ubiquitinated Pex5p in proteasomal mutants demonstrates that the ubiquitination of Pex5p also takes place in strains which are not affected in peroxisomal biogenesis, indicating that the ubiquitination of Pex5p represents a genuine stage in the Pex5p receptor cycle.

Rma1, a novel type of RING finger protein conserved from Arabidopsis to human, is a membrane-bound ubiquitin ligase

2001 ◽  
Vol 114 (10) ◽  
pp. 1949-1957 ◽  
Author(s):  
N. Matsuda ◽  
T. Suzuki ◽  
K. Tanaka ◽  
A. Nakano
Keyword(s):  
Ubiquitin Ligase ◽  
Mutational Analysis ◽  
Ring Finger ◽  
Ring Finger Protein ◽  
Finger Protein ◽  
Ubiquitin Ligase E3 ◽  
Membrane Bound ◽  
E2 Enzymes ◽  
Membrane Anchoring ◽  
Ring Finger Motif

Rma1 is a protein with a RING finger motif and a C-terminal membrane-anchoring domain and is well conserved among higher eukaryotes. We show that fusion proteins between maltose binding protein (MBP) and human or Arabidopsis Rma1 are polyubiquitinated, when incubated with the rabbit reticulocyte or the wheat germ lysate, respectively. The polyubiquitination of MBP-Rma1 has been reconstituted by incubation with purified ubiquitin, the ubiquitin-activating enzyme E1, and one of the two ubiquitin-conjugating E2 enzymes (Ubc4 or UbcH5a). Other E2 enzymes tested, E2-20k, E2-25k, Ubc3 and Ubc8, are not able to confer this modification. Mutational analysis shows that the RING finger motif of Rma1 is necessary for the auto-ubiquitination of MBP-Rma1. Thus, Rma1 represents a novel, membrane-bound type of ubiquitin ligase E3, which probably functions with the Ubc4/5 subfamily of E2. The MBP moiety but not Rma1 itself is ubiquitinated in the auto-ubiquitination reaction of MBP-Rma1. Free MBP in solution is not a substrate of Rma1. These observations indicate that bringing the substrate into its physical vicinity is very important for the action of ubiquitin ligase.

A RING Finger Motif Regulates Transforming Activity of therfp/retFusion Gene

1996 ◽  
Vol 225 (2) ◽  
pp. 627-631 ◽  
Author(s):  
Nakaba Hasegawa ◽  
Toshihide Iwashita ◽  
Naoya Asai ◽  
Hideki Murakami ◽  
Yosuke Iwata ◽  
...  
Keyword(s):  
Ring Finger ◽  
Transforming Activity ◽  
Ring Finger Motif

scholarly journals The RING Finger Motif of Photomorphogenic Repressor COP1 Specifically Interacts with the RING-H2 Motif of a NovelArabidopsisProtein

1999 ◽  
Vol 274 (39) ◽  
pp. 27674-27681 ◽  
Author(s):  
Keiko U. Torii ◽  
Chatanika D. Stoop-Myer ◽  
Haruko Okamoto ◽  
Joseph E. Coleman ◽  
Minami Matsui ◽  
...  
Keyword(s):  
Ring Finger ◽  
Ring Finger Motif

scholarly journals Rabring7, a Novel Rab7 Target Protein with a RING Finger Motif

2003 ◽  
Vol 14 (9) ◽  
pp. 3741-3752 ◽  
Author(s):  
Kouichi Mizuno ◽  
Akiko Kitamura ◽  
Takuya Sasaki
Keyword(s):  
Ring Finger ◽  
Late Endosome ◽  
Endocytic Pathway ◽  
Target Protein ◽  
Vesicle Traffic ◽  
Rab Protein ◽  
Lysosome Biogenesis ◽  
Late Endosomes ◽  
Epidermal Growth ◽  
Ring Finger Motif

Rab7, a member of the Rab family small G proteins, has been shown to regulate intracellular vesicle traffic to late endosome/lysosome and lysosome biogenesis, but the exact roles of Rab7 are still undetermined. Accumulating evidence suggests that each Rab protein has multiple target proteins that function in the exocytic/endocytic pathway. We have isolated a new Rab7 target protein, Rabring7 (Rab7-interacting RING finger protein), using a CytoTrap system. It contains an H2 type RING finger motif at the C termini. Rabring7 shows no homology with RILP, which has been reported as another Rab7 target protein. GST pull-down and coimmunoprecipitation assays demonstrate that Rabring7 specifically binds the GTP-bound form of Rab7 at the N-terminal portion. Rabring7 is found mainly in the cytosol and is recruited efficiently to late endosomes/lysosomes by the GTP-bound form of Rab7 in BHK cells. Overexpression of Rabring7 not only affects epidermal growth factor degradation but also causes the perinuclear aggregation of lysosomes, in which the accumulation of the acidotropic probe LysoTracker is remarkably enhanced. These results suggest that Rabring7 plays crucial roles as a Rab7 target protein in vesicle traffic to late endosome/lysosome and lysosome biogenesis.

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