Cytoplasmic Capes Are Nuclear Envelope Intrusions That Are Enriched in Endosomal Proteins and Depend upon βH-Spectrin and Annexin B9

View/ Open
Author
Wu, Juan
Bakerink, Katelyn J.
Evangelista, Meagan E.
Thomas, Graham H.
Published Version
https://doi.org/10.1371/journal.pone.0093680Metadata
Show full item recordCitation
Wu, Juan, Katelyn J. Bakerink, Meagan E. Evangelista, and Graham H. Thomas. 2014. “Cytoplasmic Capes Are Nuclear Envelope Intrusions That Are Enriched in Endosomal Proteins and Depend upon βH-Spectrin and Annexin B9.” PLoS ONE 9 (4): e93680. doi:10.1371/journal.pone.0093680. http://dx.doi.org/10.1371/journal.pone.0093680.Abstract
It is increasingly recognized that non-erythroid spectrins have roles remote from the plasma membrane, notably in endomembrane trafficking. The large spectrin isoform, βH, partners with Annexin B9 to modulate endosomal processing of internalized proteins. This modulation is focused on the early endosome through multivesicular body steps of endocytic processing and loss of either protein appears to cause a traffic jam before removal of ubiquitin at the multivesicular body. We previously reported that βH/Annexin B9 influenced EGF receptor signaling. While investigating this effect we noticed that mSptiz, the membrane bound precursor of the secreted EGF receptor ligand sSpitz, is located in striking intrusions of the nuclear membrane. Here we characterize these structures and identify them as ‘cytoplasmic capes’, which were previously identified in old ultrastructural studies and probably coincide with recently recognized sites of non-nuclear-pore RNA export. We show that cytoplasmic capes contain multiple endosomal markers and that their existence is dependent upon βH and Annexin B9. Diminution of these structures does not lead to a change in mSpitz processing. These results extend the endosomal influence of βH and its partner Annexin B9 to this unusual compartment at the nuclear envelope.Other Sources
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3976414/pdf/Terms of Use
This article is made available under the terms and conditions applicable to Other Posted Material, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#LAACitable link to this page
http://nrs.harvard.edu/urn-3:HUL.InstRepos:12153043
Collections
- HMS Scholarly Articles [17875]
Contact administrator regarding this item (to report mistakes or request changes)