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J Cell Biol. 2014 Oct 13;207(1):41-57. doi: 10.1083/jcb.201406037. Epub 2014 Oct 6.

The calcium-dependent ribonuclease XendoU promotes ER network formation through local RNA degradation.

Author information

1
Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114 Department of Genetics, Harvard Medical School, Boston, MA 02115.
2
Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114 Department of Genetics, Harvard Medical School, Boston, MA 02115 blower@molbio.mgh.harvard.edu.

Abstract

How cells shape and remodel organelles in response to cellular signals is a poorly understood process. Using Xenopus laevis egg extract, we found that increases in cytosolic calcium lead to the activation of an endogenous ribonuclease, XendoU. A fraction of XendoU localizes to the endoplasmic reticulum (ER) and is required for nuclear envelope assembly and ER network formation in a catalysis-dependent manner. Using a purified vesicle fusion assay, we show that XendoU functions on the surface of ER membranes to promote RNA cleavage and ribonucleoprotein (RNP) removal. Additionally, RNA removal from the surface of vesicles by RNase treatment leads to increased ER network formation. Using human tissue culture cells, we found that hEndoU localizes to the ER, where it promotes the formation of ER tubules in a catalysis-dependent manner. Together, these results demonstrate that calcium-activated removal of RNA from membranes by XendoU promotes and refines ER remodeling and the formation of tubular ER.

Comment in

PMID:
25287301
PMCID:
PMC4195833
DOI:
10.1083/jcb.201406037
[Indexed for MEDLINE]
Free PMC Article

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