Back to Search
Start Over
Lunapark Is a Component of a Ubiquitin Ligase Complex Localized to the Endoplasmic Reticulum Three-way Junctions
- Source :
- Journal of Biological Chemistry. 291:18252-18262
- Publication Year :
- 2016
- Publisher :
- Elsevier BV, 2016.
-
Abstract
- The endoplasmic reticulum (ER) network comprises sheets and tubules that are connected by dynamic three-way junctions. Lunapark (Lnp) localizes to and stabilizes ER three-way junctions by antagonizing the small GTPase Atlastin, but how Lnp shapes the ER network is unclear. Here, we used an affinity purification approach and mass spectrometry to identify Lnp as an interacting partner of the ER protein quality control ubiquitin ligase gp78. Accordingly, Lnp purified from mammalian cells has a ubiquitin ligase activity in vitro. Intriguingly, biochemical analyses show that this activity can be attributed not only to associated ubiquitin ligase, but also to an intrinsic ubiquitin ligase activity borne by Lnp itself. This activity is contained in the N-terminal 45 amino acids of Lnp although this segment does not share homology to any known ubiquitin ligase motifs. Despite its interaction with gp78, Lnp does not seem to have a broad function in degradation of misfolded ER proteins. On the other hand, the N-terminal ubiquitin ligase-bearing motif is required for the ER three-way junction localization of Lnp. Our study identifies a new type of ubiquitin ligase and reveals a potential link between ubiquitin and ER morphology regulation.
- Subjects :
- 0301 basic medicine
Atlastin
Amino Acid Motifs
Biology
Endoplasmic Reticulum
Biochemistry
03 medical and health sciences
Ubiquitin
GTP-Binding Proteins
Chlorocebus aethiops
Animals
Humans
Small GTPase
Molecular Biology
Homeodomain Proteins
chemistry.chemical_classification
Endoplasmic reticulum
Membrane Proteins
Cell Biology
Amino acid
Cell biology
Ubiquitin ligase
Receptors, Autocrine Motility Factor
Protein Transport
030104 developmental biology
chemistry
Protein Synthesis and Degradation
Ubiquitin ligase complex
COS Cells
biology.protein
Protein folding
HeLa Cells
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 291
- Database :
- OpenAIRE
- Journal :
- Journal of Biological Chemistry
- Accession number :
- edsair.doi.dedup.....db3bbc58edbc5c33ada8fa0b60991cae