scholarly journals Direct Binding to Rsp5p Regulates Ubiquitination-independent Vacuolar Transport of Sna3p

2007 ◽  
Vol 18 (5) ◽  
pp. 1781-1789 ◽  
Author(s):  
Hadiya Watson ◽  
Juan S. Bonifacino
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ubiquitin Ligase ◽  
Adaptor Protein ◽  
Direct Interaction ◽  
Integral Membrane Proteins ◽  
Multivesicular Bodies ◽  
Hect Domain ◽  
Ww Domains ◽  
Cytosolic Domains ◽  
Direct Binding

The sorting of integral membrane proteins such as carboxypeptidase S (Cps1p) into the luminal vesicles of multivesicular bodies (MVBs) in Saccharomyces cerevisiae requires ubiquitination of their cytosolic domains by the ubiquitin ligases Rsp5p and/or Tul1p. An exception is Sna3p, which does not require ubiquitination for entry into MVBs. The mechanism underlying this ubiquitination-independent MVB sorting pathway has not yet been characterized. Here, we show that Sna3p sorting into the MVB pathway depends on a direct interaction between a PPAY motif within its C-terminal cytosolic tail and the WW domains of Rsp5p. Disruption of this interaction inhibits vacuolar targeting of Sna3p and causes its accumulation in a compartment that overlaps only partially with MVBs. Surprisingly, Sna3p does require a functional ubiquitin-ligase HECT domain within Rsp5p; however, the dependence of Sna3p on HECT domain activity is distinct from that of Cps1p. Last, we show that Sna3p requires neither Tul1p nor the transmembrane adaptor protein Bsd2p for its MVB sorting. Our data demonstrate that Sna3p follows a novel ubiquitination-independent, but Rsp5p-mediated, sorting pathway to the vacuole.

scholarly journals Direct Binding to Rsp5 Mediates Ubiquitin-independent Sorting of Sna3 via the Multivesicular Body Pathway

2007 ◽  
Vol 18 (2) ◽  
pp. 697-706 ◽  
Author(s):  
Matthew W. McNatt ◽  
Ian McKittrick ◽  
Matthew West ◽  
Greg Odorizzi
Keyword(s):  
Multivesicular Body ◽  
Integral Membrane Proteins ◽  
Multivesicular Bodies ◽  
Wild Type ◽  
Independent Function ◽  
Broad Distribution ◽  
Ww Domains ◽  
Cargo Protein ◽  
Cytosolic Domains ◽  
Direct Binding

The sorting of most integral membrane proteins into the lumenal vesicles of multivesicular bodies (MVBs) is dependent on the attachment of ubiquitin (Ub) to their cytosolic domains. However, Ub is not required for sorting of Sna3, an MVB vesicle cargo protein in yeast. We show that Sna3 circumvents Ub-mediated recognition by interacting directly with Rsp5, an E3 Ub ligase that catalyzes monoubiquitination of MVB vesicle cargoes. The PPAY motif in the C-terminal cytosolic domain of Sna3 binds the WW domains in Rsp5, and Sna3 is polyubiquitinated as a consequence of this association. However, Ub does not appear to be required for transport of Sna3 via the MVB pathway because its sorting occurs under conditions in which its ubiquitination is impaired. Consistent with Ub-independent function of the MVB pathway, we show by electron microscopy that the formation of MVB vesicles does not require Rsp5 E3 ligase activity. However, cells expressing a catalytically disabled form of Rsp5 have a greater frequency of smaller MVB vesicles compared with the relatively broad distribution of vesicles seen in MVBs of wild-type cells, suggesting that the formation of MVB vesicles is influenced by Rsp5-mediated ubiquitination.

scholarly journals Dual Sorting of the Saccharomyces cerevisiae Vacuolar Protein Sna4p

2009 ◽  
Vol 8 (3) ◽  
pp. 278-286 ◽  
Author(s):  
W. Pokrzywa ◽  
B. Guerriat ◽  
J. Dodzian ◽  
P. Morsomme
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Alkaline Phosphatase ◽  
Membrane Protein ◽  
Ubiquitin Ligase ◽  
Protein Complex ◽  
Adaptor Protein ◽  
Vacuolar Membrane ◽  
Multivesicular Bodies ◽  
Small Family ◽  
Vacuolar Protein

ABSTRACT Sna4p, a vacuolar membrane protein, belongs to a small family of proteins conserved in plants and fungi. It is transported to the vacuolar membrane via the alkaline phosphatase (ALP) pathway, which bypasses the multivesicular bodies (MVBs). Here, we show that transfer of Sna4p by the ALP route involves the AP-3 adaptor protein complex, which binds to an acidic dileucine sorting signal in the cytoplasmic region of Sna4p. In addition, Sna4p can use the MVB pathway by using a PPPY motif, which is involved in the interaction with ubiquitin ligase Rsp5p. Deletion or mutation of the Sna4p PPPY motif or a low level of Rsp5p inhibits the entrance of Sna4p into MVBs. Sna4p is polyubiquitylated on its only lysine, and Sna4p lacking this lysine shows defective MVB sorting. These data indicate that Sna4p has two functional motifs, one for interaction with the AP-3 complex, followed by entry into the ALP pathway, and one for binding Rsp5p, which directs the protein to the MVB pathway. The presence of these two motifs allows Sna4p to localize to both the vacuolar membrane and the lumen.

scholarly journals The E3 Ubiquitin Ligase Atrophin Interacting Protein 4 Binds Directly To The Chemokine Receptor CXCR4 Via a Novel WW Domain-mediated Interaction

2009 ◽  
Vol 20 (5) ◽  
pp. 1324-1339 ◽  
Author(s):  
Deepali Bhandari ◽  
Seth L. Robia ◽  
Adriano Marchese
Keyword(s):  
Ubiquitin Ligase ◽  
Chemokine Receptor ◽  
E3 Ubiquitin Ligase ◽  
Adaptor Protein ◽  
Interacting Protein ◽  
Binding Motifs ◽  
Ww Domain ◽  
Ww Domains ◽  
Chemokine Receptor Cxcr4 ◽  
Carboxy Terminal

The E3 ubiquitin ligase atrophin interacting protein 4 (AIP4) mediates ubiquitination and down-regulation of the chemokine receptor CXCR4. AIP4 belongs to the Nedd4-like homologous to E6-AP carboxy terminus domain family of E3 ubiquitin ligases, which typically bind proline-rich motifs within target proteins via the WW domains. The intracellular domains of CXCR4 lack canonical WW domain binding motifs; thus, whether AIP4 is targeted to CXCR4 directly or indirectly via an adaptor protein remains unknown. Here, we show that AIP4 can interact directly with CXCR4 via a novel noncanonical WW domain-mediated interaction involving serine residues 324 and 325 within the carboxy-terminal tail of CXCR4. These serine residues are critical for mediating agonist-promoted binding of AIP4 and subsequent ubiquitination and degradation of CXCR4. These residues are phosphorylated upon agonist activation and phosphomimetic mutants show enhanced binding to AIP4, suggesting a mechanism whereby phosphorylation mediates the interaction between CXCR4 and AIP4. Our data reveal a novel noncanonical WW domain-mediated interaction involving phosphorylated serine residues in the absence of any proline residues and suggest a novel mechanism whereby an E3 ubiquitin ligase is targeted directly to an activated G protein-coupled receptor.

scholarly journals WW domain–mediated regulation and activation of E3 ubiquitin ligase Suppressor of Deltex

2018 ◽  
Vol 293 (43) ◽  
pp. 16697-16708 ◽  
Author(s):  
Weiyi Yao ◽  
Zelin Shan ◽  
Aihong Gu ◽  
Minjie Fu ◽  
Zhifeng Shi ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Cell Cycle Progression ◽  
Regulatory Mechanism ◽  
Cycle Progression ◽  
Hect Domain ◽  
Ww Domain ◽  
Ww Domains ◽  
E3 Ligases ◽  
Regulation Of Cell Cycle ◽  
Py Motif

The Nedd4 family E3 ligases Itch and WWP1/2 play crucial roles in the regulation of cell cycle progression and apoptosis and are closely correlated with cancer development and metastasis. It has been recently shown that the ligase activities of Itch and WWP1/2 are tightly regulated, with the HECT domain sequestered intramolecularly by a linker region connecting WW2 and WW3. Here, we show that a similar autoinhibitory mechanism is utilized by the Drosophila ortholog of Itch and WWP1/2, Suppressor of Deltex (Su(dx)). We show that Su(dx) adopts an inactive steady state with the WW domain region interacting with the HECT domain. We demonstrate that both the linker and preceding WW2 are required for the efficient binding and regulation of Su(dx) HECT. Recruiting the multiple-PY motif–containing adaptor dNdfip via WW domains relieves the inhibitory state of Su(dx) and leads to substrate (e.g. Notch) ubiquitination. Our study demonstrates an evolutionarily conservative mechanism governing the regulation and activation of some Nedd4 family E3 ligases. Our results also suggest a dual regulatory mechanism for specific Notch down-regulation via dNdfip–Su(dx)–mediated Notch ubiquitination.

scholarly journals Pex3 peroxisome biogenesis proteins function in peroxisome inheritance as class V myosin receptors

2009 ◽  
Vol 187 (2) ◽  
pp. 233-246 ◽  
Author(s):  
Jinlan Chang ◽  
Fred D. Mast ◽  
Andrei Fagarasanu ◽  
Dorian A. Rachubinski ◽  
Gary A. Eitzen ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mother Cell ◽  
Direct Interaction ◽  
Integral Membrane Proteins ◽  
Eukaryotic Cells ◽  
General Mechanism ◽  
Peroxisome Biogenesis ◽  
Class V ◽  
Established Role ◽  
In Cells

In Saccharomyces cerevisiae, peroxisomal inheritance from mother cell to bud is conducted by the class V myosin motor, Myo2p. However, homologues of S. cerevisiae Myo2p peroxisomal receptor, Inp2p, are not readily identifiable outside the Saccharomycetaceae family. Here, we demonstrate an unexpected role for Pex3 proteins in peroxisome inheritance. Both Pex3p and Pex3Bp are peroxisomal integral membrane proteins that function as peroxisomal receptors for class V myosin through direct interaction with the myosin globular tail. In cells lacking Pex3Bp, peroxisomes are preferentially retained by the mother cell, whereas most peroxisomes gather and are transferred en masse to the bud in cells overexpressing Pex3Bp or Pex3p. Our results reveal an unprecedented role for members of the Pex3 protein family in peroxisome motility and inheritance in addition to their well-established role in peroxisome biogenesis at the endoplasmic reticulum. Our results point to a temporal link between peroxisome formation and inheritance and delineate a general mechanism of peroxisome inheritance in eukaryotic cells.

scholarly journals Hse1, a Component of the Yeast Hrs-STAM Ubiquitin-sorting Complex, Associates with Ubiquitin Peptidases and a Ligase to Control Sorting Efficiency into Multivesicular Bodies

2007 ◽  
Vol 18 (1) ◽  
pp. 324-335 ◽  
Author(s):  
Jihui Ren ◽  
Younghoon Kee ◽  
Jon M. Huibregtse ◽  
Robert C. Piper
Keyword(s):  
Functional Analysis ◽  
Membrane Proteins ◽  
Ubiquitin Ligase ◽  
Integral Membrane Proteins ◽  
Multivesicular Bodies ◽  
C Terminus ◽  
Cargo Proteins ◽  
Sorting Receptor ◽  
Sorting Efficiency ◽  
Novel Protein

Ubiquitinated integral membrane proteins are delivered to the interior of the lysosome/vacuole for degradation. This process relies on specific ubiquitination of potential cargo and recognition of that Ub-cargo by sorting receptors at multiple compartments. We show that the endosomal Hse1-Vps27 sorting receptor binds to ubiquitin peptidases and the ubiquitin ligase Rsp5. Hse1 is linked to Rsp5 directly via a PY element within its C-terminus and through a novel protein Hua1, which recruits a complex of Rsp5, Rup1, and Ubp2. The SH3 domain of Hse1 also binds to the deubiquitinating protein Ubp7. Functional analysis shows that when both modes of Rsp5 association with Hse1 are altered, sorting of cargo that requires efficient ubiquitination for entry into the MVB is blocked, whereas sorting of cargo containing an in-frame addition of ubiquitin is normal. Further deletion of Ubp7 restores sorting of cargo when the Rsp5:Hse1 interaction is compromised suggesting that both ubiquitin ligases and peptidases associate with the Hse1-Vps27 sorting complex to control the ubiquitination status and sorting efficiency of cargo proteins. Additionally, we find that disruption of UBP2 and RUP1 inhibits MVB sorting of some cargos suggesting that Rsp5 requires association with Ubp2 to properly ubiquitinate cargo for efficient MVB sorting.

Regulation of Nedd4-2 self-ubiquitination and stability by a PY motif located within its HECT-domain

2008 ◽  
Vol 415 (1) ◽  
pp. 155-163 ◽  
Author(s):  
M. Christine Bruce ◽  
Voula Kanelis ◽  
Fatemeh Fouladkou ◽  
Anne Debonneville ◽  
Olivier Staub ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Down Regulation ◽  
Hect Domain ◽  
Ww Domains ◽  
Protein Protein Interaction ◽  
C Terminus ◽  
Subsequent Degradation ◽  
Interaction Domains ◽  
The Stability ◽  
Py Motif

Ubiquitin ligases play a pivotal role in substrate recognition and ubiquitin transfer, yet little is known about the regulation of their catalytic activity. Nedd4 (neural-precursor-cell-expressed, developmentally down-regulated 4)-2 is an E3 ubiquitin ligase composed of a C2 domain, four WW domains (protein–protein interaction domains containing two conserved tryptophan residues) that bind PY motifs (L/PPXY) and a ubiquitin ligase HECT (homologous with E6-associated protein C-terminus) domain. In the present paper we show that the WW domains of Nedd4-2 bind (weakly) to a PY motif (LPXY) located within its own HECT domain and inhibit auto-ubiquitination. Pulse–chase experiments demonstrated that mutation of the HECT PY-motif decreases the stability of Nedd4-2, suggesting that it is involved in stabilization of this E3 ligase. Interestingly, the HECT PY-motif mutation does not affect ubiquitination or down-regulation of a known Nedd4-2 substrate, ENaC (epithelial sodium channel). ENaC ubiquitination, in turn, appears to promote Nedd4-2 self-ubiquitination. These results support a model in which the inter- or intra-molecular WW-domain–HECT PY-motif interaction stabilizes Nedd4-2 by preventing self-ubiquitination. Substrate binding disrupts this interaction, allowing self-ubiquitination of Nedd4-2 and subsequent degradation, resulting in down-regulation of Nedd4-2 once it has ubiquitinated its target. These findings also point to a novel mechanism employed by a ubiquitin ligase to regulate itself differentially compared with substrate ubiquitination and stability.

scholarly journals Multiple Interactions Drive Adaptor-Mediated Recruitment of the Ubiquitin Ligase Rsp5 to Membrane Proteins In Vivo and In Vitro

2007 ◽  
Vol 18 (7) ◽  
pp. 2429-2440 ◽  
Author(s):  
James A. Sullivan ◽  
Michael J. Lewis ◽  
Elina Nikko ◽  
Hugh R.B. Pelham
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Membrane Proteins ◽  
Ubiquitin Ligase ◽  
Multivesicular Body ◽  
Ww Domains ◽  
Absolute Requirement ◽  
Multiple Interactions ◽  
Sequential Assembly

Recognition of membrane proteins by the Nedd4/Rsp5 ubiquitin ligase family is a critical step in their targeting to the multivesicular body pathway. Some substrates contain “PY” motifs (PPxY), which bind to WW domains in the ligase. Others lack PY motifs and instead rely on adaptors that recruit the ligase to them. To investigate the mechanism of adaptor-mediated ubiquitination, we have characterized the interactions between the adaptor Bsd2, the ubiquitin ligase Rsp5, and the membrane proteins Cps1, Tre1, and Smf1 from Saccharomyces cerevisiae. We have reconstituted adaptor-mediated modification of Cps1 and Tre1 in vitro, and we show that two PY motifs in Bsd2 and two WW domains (WW2 and WW3) in Rsp5 are crucial for this. The binding of a weak noncanonical DMAPSY motif in Bsd2 to WW3 is an absolute requirement for Bsd2 adaptor function. We show that sorting of the manganese transporter Smf1, which requires both Bsd2 and Tre1, depends upon two PY motifs in Bsd2 and one motif in Tre1 but only two WW domains in Rsp5. We suggest that sequential assembly of first a Bsd2/Rsp5 complex, then a Tre1/Bsd2/Rsp5 complex followed by a rearrangement of PY–WW interactions is required for the ubiquitination of Smf1.

scholarly journals The Zn-finger of Saccharomyces cerevisiae Rad18 and its adjacent region mediate interaction with Rad5

2021 ◽  
Author(s):  
Orsolya Frittmann ◽  
Vamsi K Gali ◽  
Miklos Halmai ◽  
Robert Toth ◽  
Zsuzsanna Gyorfy ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Damage ◽  
Ubiquitin Ligase ◽  
Dna Lesions ◽  
Template Switching ◽  
Adjacent Region ◽  
Yeast Two Hybrid ◽  
Replication Complex ◽  
Two Hybrid

Abstract DNA damages that hinder the movement of the replication complex can ultimately lead to cell death. To avoid that, cells possess several DNA damage bypass mechanisms. The Rad18 ubiquitin ligase controls error-free and mutagenic pathways that help the replication complex to bypass DNA lesions by monoubiquitylating PCNA at stalled replication forks. In Saccharomyces cerevisiae, two of the Rad18 governed pathways are activated by monoubiquitylated PCNA and they involve translesion synthesis polymerases, whereas a third pathway needs subsequent polyubiquitylation of the same PCNA residue by another ubiquitin ligase the Rad5 protein, and it employs template switching. The goal of this study was to dissect the regulatory role of the multidomain Rad18 in DNA damage bypass using a structure-function based approach. Investigating deletion and point mutant RAD18 variants in yeast genetic and yeast two-hybrid assays we show that the Zn-finger of Rad18 mediates its interaction with Rad5, and the N-terminal adjacent region is also necessary for Rad5 binding. Moreover, results of the yeast two-hybrid and in vivo ubiquitylation experiments raise the possibility that direct interaction between Rad18 and Rad5 might not be necessary for the function of the Rad5 dependent pathway. The presented data also reveal that yeast Rad18 uses different domains to mediate its association with itself and with Rad5. Our results contribute to better understanding of the complex machinery of DNA damage bypass pathways.

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