Peripheral endoplasmic reticulum localization of the Gp78 ubiquitin ligase activity

2012 ◽  
Vol 125 (7) ◽  
pp. 1727-1737 ◽  
Author(s):  
P. St-Pierre ◽  
T. Dang ◽  
B. Joshi ◽  
I. R. Nabi
2013 ◽  
Vol 24 (7) ◽  
pp. 890-900 ◽  
Author(s):  
Dimitrios Zattas ◽  
David J. Adle ◽  
Eric M. Rubenstein ◽  
Mark Hochstrasser

Two conserved ubiquitin ligases, Hrd1 and Doa10, mediate most endoplasmic reticulum–associated protein degradation (ERAD) in yeast. Degradation signals (degrons) recognized by these ubiquitin ligases remain poorly characterized. Doa10 recognizes the Deg1 degron from the MATα2 transcription factor. We previously found that deletion of the gene (NAT3) encoding the catalytic subunit of the NatB N-terminal acetyltransferase weakly stabilized a Deg1-fusion protein. By contrast, a recent analysis of several MATα2 derivatives suggested that N-terminal acetylation of these proteins by NatB was crucial for recognition by Doa10. We now analyze endogenous MATα2 degradation in cells lacking NatB and observe minimal perturbation relative to wild-type cells. However, NatB mutation strongly impairs degradation of ER-luminal Hrd1 substrates. This unexpected defect derives from a failure of Der1, a Hrd1 complex subunit, to be N-terminally acetylated in NatB mutant yeast. We retargeted Der1 to another acetyltransferase to show that it is the only ERAD factor requiring N-terminal acetylation. Preventing Der1 acetylation stimulates its proteolysis via the Hrd1 pathway, at least partially accounting for the ERAD defect observed in the absence of NatB. These results reveal an important role for N-terminal acetylation in controlling Hrd1 ligase activity toward a specific class of ERAD substrates.


2011 ◽  
Vol 286 (27) ◽  
pp. 24426-24433 ◽  
Author(s):  
Justine P. Lu ◽  
Yuan Wang ◽  
Danielle A. Sliter ◽  
Margaret M. P. Pearce ◽  
Richard J. H. Wojcikiewicz

Inositol 1,4,5-trisphosphate (IP3) receptors are endoplasmic reticulum membrane calcium channels that, upon activation, are degraded via the ubiquitin-proteasome pathway. While searching for novel mediators of IP3 receptor processing, we discovered that RNF170, an uncharacterized RING domain-containing protein, associates rapidly with activated IP3 receptors. RNF170 is predicted to have three membrane-spanning helices, is localized to the ER membrane, and possesses ubiquitin ligase activity. Depletion of endogenous RNF170 by RNA interference inhibited stimulus-induced IP3 receptor ubiquitination, and degradation and overexpression of a catalytically inactive RNF170 mutant suppressed stimulus-induced IP3 receptor processing. A substantial proportion of RNF170 is constitutively associated with the erlin1/2 (SPFH1/2) complex, which has been shown previously to bind to IP3 receptors immediately after their activation. Depletion of RNF170 did not affect the binding of the erlin1/2 complex to stimulated IP3 receptors, whereas erlin1/2 complex depletion inhibited RNF170 binding. These results suggest a model in which the erlin1/2 complex recruits RNF170 to activated IP3 receptors where it mediates IP3 receptor ubiquitination. Thus, RNF170 plays an essential role in IP3 receptor processing via the ubiquitin-proteasome pathway.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hiroaki Kajiho ◽  
Yasunori Yamamoto ◽  
Toshiaki Sakisaka

Abstract Endoplasmic reticulum (ER) tubules connect each other by three-way junctions, resulting in a tubular ER network. Oligomerization of three-way junction protein lunapark (Lnp) is important for its localization and the three-way junction stability. On the other hand, Lnp has an N-terminal ubiquitin ligase activity domain, which is also important for the three-way junction localization. To understand the mode of action of Lnp, we isolated Cullin-associated and neddylation-dissociated 1 (CAND1), a regulator of Skp1-Cul1-F-box (SCF) ubiquitin ligase, as a Lnp-binding protein by affinity chromatography. CAND1 and Lnp form a higher-molecular-weight complex in vitro, while they do not co-localize at the three-way junctions. CAND1 reduces the auto-ubiquitination activity of Lnp. CAND1 knockdown enhances proteasomal degradation of Lnp and reduces the tubular ER network in mammalian cells. These results suggest that CAND1 has the potency to promote the formation of the higher-molecular-weight complex with Lnp and reduce the auto-ubiquitination activity of Lnp, thereby regulating the three-way junction stability of the tubular ER network.


2005 ◽  
Vol 25 (4) ◽  
pp. 1437-1445 ◽  
Author(s):  
Sébastien Storck ◽  
Frédéric Delbos ◽  
Nicolas Stadler ◽  
Catherine Thirion-Delalande ◽  
Florence Bernex ◽  
...  

ABSTRACT The Notch signaling pathway controls several cell fate decisions during lymphocyte development, from T-cell lineage commitment to the peripheral differentiation of B and T lymphocytes. Deltex-1 is a RING finger ubiquitin ligase which is conserved from Drosophila to humans and has been proposed to be a regulator of Notch signaling. Its pattern of lymphoid expression as well as gain-of-function experiments suggest that Deltex-1 regulates both B-cell lineage and splenic marginal-zone B-cell commitment. Deltex-1 was also found to be highly expressed in germinal-center B cells. To investigate the physiological function of Deltex-1, we generated a mouse strain lacking the Deltex-1 RING finger domain, which is essential for its ubiquitin ligase activity. Deltex-1Δ/Δ mice were viable and fertile. A detailed histological analysis did not reveal any defects in major organs. T- and B-cell development was normal, as were humoral responses against T-dependent and T-independent antigens. These data indicate that the Deltex-1 ubiquitin ligase activity is dispensable for mouse development and immune function. Possible compensatory mechanisms, in particular those from a fourth Deltex gene identified during the course of this study, are also discussed.


2002 ◽  
Vol 10 (1) ◽  
pp. 55-67 ◽  
Author(s):  
Yuzuru Imai ◽  
Mariko Soda ◽  
Shigetsugu Hatakeyama ◽  
Takumi Akagi ◽  
Tsutomu Hashikawa ◽  
...  

Oncogene ◽  
2010 ◽  
Vol 29 (43) ◽  
pp. 5818-5827 ◽  
Author(s):  
T Qian ◽  
J-Y Lee ◽  
J-H Park ◽  
H-J Kim ◽  
G Kong

Plant Science ◽  
2007 ◽  
Vol 173 (2) ◽  
pp. 269-275 ◽  
Author(s):  
Bong Soo Park ◽  
Wan Gyu Sang ◽  
Song Yion Yeu ◽  
Yang Do Choi ◽  
Nam-Chon Paek ◽  
...  

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Lin Hu ◽  
Jiafeng Xu ◽  
Xiaomei Xie ◽  
Yiwen Zhou ◽  
Panfeng Tao ◽  
...  

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