A Chinese hamster cell cycle mutant arrested at G2 phase has a temperature-sensitive ubiquitin-activating enzyme, E1.

Kulka, Richard G.; Raboy, Bilha; Schuster, Roswitha; Parag, H A; Diamond, Gill; Ciechanover, Aaron; Marcus, Menashe

doi:10.1016/s0021-9258(19)37648-3

Cited by 163 publications

(20 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To substantiate the role of Ub conjugation in the degradation of the r⌬F508 and ⌬70 CFTR, we measured the cell surface stability of mutants in ts20 CHO cells, harboring the thermosensitive E1 Ub-activating enzyme. Consistent with the results of Kulka et al (1988), the E1 enzyme was inactivated at 40ЊC in ts20 cells, whereas the expression level of the wt E1 remained unaltered in E36 cells, as shown by immunoblot analysis (Fig. 6 a).…”

Section: The Activity Of Ubiquitination Enzyme Cascade Is Required For the Endosomal Sorting Of Misfolded Cftr Toward Lysosomal Degradatisupporting

confidence: 89%

Misfolding diverts CFTR from recycling to degradation

Sharma

Pampinella

Nemes

et al. 2004

The Journal of Cell Biology

307

394

View full text Add to dashboard Cite

To investigate the degradation mechanism of misfolded membrane proteins from the cell surface, we used mutant cystic fibrosis transmembrane conductance regulators (CFTRs) exhibiting conformational defects in post-Golgi compartments. Here, we show that the folding state of CFTR determines the post-endocytic trafficking of the channel. Although native CFTR recycled from early endosomes back to the cell surface, misfolding prevented recycling and facilitated lysosomal targeting by promoting the ubiquitination of the channel. Rescuing the folding defect or down-regulating the E1 ubiquitin (Ub)-activating enzyme stabilized the mutant CFTR without interfering with its internalization. These observations with the preferential association of mutant CFTRs with Hrs, STAM-2, TSG101, hVps25, and hVps32, components of the Ub-dependent endosomal sorting machinery, establish a functional link between Ub modification and lysosomal degradation of misfolded CFTR from the cell surface. Our data provide evidence for a novel cellular mechanism of CF pathogenesis and suggest a paradigm for the quality control of plasma membrane proteins involving the coordinated function of ubiquitination and the Ub-dependent endosomal sorting machinery.

show abstract

Section: The Activity Of Ubiquitination Enzyme Cascade Is Required For the Endosomal Sorting Of Misfolded Cftr Toward Lysosomal Degradatisupporting

confidence: 89%

Misfolding diverts CFTR from recycling to degradation

Sharma

Pampinella

Nemes

et al. 2004

The Journal of Cell Biology

307

394

View full text Add to dashboard Cite

show abstract

“…Chaperone-mediated transfer of proteins into lysosomes is enhanced in cells upon exposure to stress. However, this effect is dependent upon the synthesis of hsp73 which requires a minimum of 2 h under stress conditions (19). The heat stress-induced acceleration in protein degradation seen in the E36 cells is already detected by 1 h (12).…”

Section: Discussionmentioning

confidence: 98%

“…This reduction may be the result of E1 inactivation or reflect volumetric changes in the autolysosome compartment. Kulka et al have shown that in ts20 cells, the cellular amounts of ubiquitinated proteins are dramatically decreased coincident with heat inactivation of E1 (19). At this time, it is not clear whether this absence of ubiquitin conjugates is a cause of or only an association with the defect in autophagic vacuole maturation.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Ubiquitin-activating enzyme, E1, is associated with maturation of autophagic vacuoles.

Lenk

Dunn

Trausch

et al. 1992

The Journal of Cell Biology

Self Cite

View full text Add to dashboard Cite

Abstract. The ubiquitin-activating enzyme, El, is required for initiating a multi-step pathway for the covalent linkage of ubiquitin to target proteins. A CHO cell line containing a mutant thermolabile El, ts20, has been shown to be defective in stress-induced degradation of proteins at restrictive temperature (Gropper et al., 1991. J. Biol. Chem. 266:3602-3610). Parental E36 cells responded to restrictive temperature by stimulating lysosome-mediated protein degradation twofold. Such a response was not observed in ts20 cells. The absence of accelerated degradation in these cells at 39.5~ was accompanied by an accumulation of autolysosomes. The fractional volume of these degradative autophagic vacuoles was at least sixfold greater than that observed for either E36 cells at 30.5 ~ or 39.5~ or ts20 cells at 30.5~ These vacuoles were acidic and contained both acid phosphatase and cathepsin L, but, unlike the autolysosomes observed in E36 cells, ubiquitin-conjugated proteins were conspicuously absent. Combined, our results suggest that in ts20 cells, which are unable to generate ubiquitin-protein conjugates due to heat inactivation of El, the formation and maturation of autophagosomes into autolysosomes is normal, but the conversion of autolysosomes into residual bodies is disrupted.

show abstract

“…these cells carry ts mutations in their genes for E1 enzyme, and that the activity of E1 is required for ATP-dependent proteolysis, as well as for other (possibly proteolysis-mediated) cellular functions (Finley et al, 1984;Ciechanover et al, 1984;Kulka et al, 1988;Aysawa et al, 1992;Nishitani et al, 1992). A gene required for spermatogenesis was identified in the Sxr (sex-reversed) region of the mouseY chromosome and shown to encode an E1 enzyme whose expression is testis-specific (Mitchel et al, 1991;Kay et al, 1991).…”

mentioning

confidence: 99%

An Essential Yeast Gene Encoding a Homolog of Ubiquitin-activating Enzyme

Dohmen

Stappen

McGrath

et al. 1995

Journal of Biological Chemistry

194

186

View full text Add to dashboard Cite

Ubiquitin (Ub) activation by the Ub-activating (E1) enzyme is the initial and essential step common to all of the known processes that involve post-translational conjugation of Ub to itself or other proteins. The "activated" Ub, linked via a thioester bond to a specific cysteine residue in one of several Ub-conjugating (E2) enzymes, which catalyze the formation of isopeptide bonds between the C-terminal glycine of Ub and lysine residues of acceptor proteins. In the yeast Saccharomyces cerevisiae, a 114-kDa E1 enzyme is encoded by an essential gene termed UBA1 (McGrath, J.P., Jentsch, S., and Varshavsky, A. (1991) EMBO J. 10, 227-236). We describe the isolation and analysis of another essential gene, termed UBA2, that encodes a 71-kDa protein with extensive sequence similarities to both the UBA1-encoded yeast E1 and E1 enzymes of other organisms. The regions of similarities between Uba1p and Uba2p encompass a putative ATP-binding site as well as a sequence that is highly conserved between the known E1 enzymes and contains the active-site cysteine of E1. This cysteine is shown to be required for an essential function of Uba2p, suggesting that Uba2p-catalyzed reactions involved a transient thioester bond between Uba2p and either Ub or another protein. Uba2p is located largely in the nucleus. The putative nuclear localization signal of Uba2p is near its C terminus. The Uba1p (E1 enzyme) and Uba2p cannot complement each others essential functions even if their subcellular localization is altered by mutagenesis. Uba2p appears to interact with itself and several other S. cerevisiae proteins with apparent molecular masses of 52, 63, 87, and 120 kDa. Uba2p is multiubiquitinated in vivo, suggesting that at least a fraction of Uba2p is metabolically unstable. Uba2p is likely to be a component of the Ub system that functions as either an E2 or E1/E2 enzyme.

show abstract

A Chinese hamster cell cycle mutant arrested at G2 phase has a temperature-sensitive ubiquitin-activating enzyme, E1.

Cited by 163 publications

References 43 publications

Misfolding diverts CFTR from recycling to degradation

Misfolding diverts CFTR from recycling to degradation

Ubiquitin-activating enzyme, E1, is associated with maturation of autophagic vacuoles.

An Essential Yeast Gene Encoding a Homolog of Ubiquitin-activating Enzyme

Contact Info

Product

Resources

About