Cytoplasmic capes are nuclear envelope intrusions that are enriched in endosomal proteins and depend upon βH-spectrin and Annexin B9.

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 endo...

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Main Authors: Juan Wu, Katelyn J Bakerink, Meagan E Evangelista, Graham H Thomas
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2014-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3976414?pdf=render
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author Juan Wu
Katelyn J Bakerink
Meagan E Evangelista
Graham H Thomas
author_facet Juan Wu
Katelyn J Bakerink
Meagan E Evangelista
Graham H Thomas
author_sort Juan Wu
collection DOAJ
description 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.
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spelling doaj.art-6b9fedd8f8b94556bcac036a59c3dd292022-12-22T02:00:19ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-0194e9368010.1371/journal.pone.0093680Cytoplasmic capes are nuclear envelope intrusions that are enriched in endosomal proteins and depend upon βH-spectrin and Annexin B9.Juan WuKatelyn J BakerinkMeagan E EvangelistaGraham H ThomasIt 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.http://europepmc.org/articles/PMC3976414?pdf=render
spellingShingle Juan Wu
Katelyn J Bakerink
Meagan E Evangelista
Graham H Thomas
Cytoplasmic capes are nuclear envelope intrusions that are enriched in endosomal proteins and depend upon βH-spectrin and Annexin B9.
PLoS ONE
title Cytoplasmic capes are nuclear envelope intrusions that are enriched in endosomal proteins and depend upon βH-spectrin and Annexin B9.
title_full Cytoplasmic capes are nuclear envelope intrusions that are enriched in endosomal proteins and depend upon βH-spectrin and Annexin B9.
title_fullStr Cytoplasmic capes are nuclear envelope intrusions that are enriched in endosomal proteins and depend upon βH-spectrin and Annexin B9.
title_full_unstemmed Cytoplasmic capes are nuclear envelope intrusions that are enriched in endosomal proteins and depend upon βH-spectrin and Annexin B9.
title_short Cytoplasmic capes are nuclear envelope intrusions that are enriched in endosomal proteins and depend upon βH-spectrin and Annexin B9.
title_sort cytoplasmic capes are nuclear envelope intrusions that are enriched in endosomal proteins and depend upon βh spectrin and annexin b9
url http://europepmc.org/articles/PMC3976414?pdf=render
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