Exportin Crm1 is repurposed as a docking protein to generate microtubule organizing centers at the nuclear pore
- University of Edinburgh, United Kingdom
- National Institute of Information and Communications Technology, Japan
Abstract
Non-centrosomal microtubule organizing centers (MTOCs) are important for microtubule organization in many cell types. In fission yeast Schizosaccharomyces pombe, the protein Mto1, together with partner protein Mto2 (Mto1/2 complex), recruits the g-tubulin complex to multiple non-centrosomal MTOCs, including the nuclear envelope (NE). Here, we develop a comparative-interactome mass spectrometry approach to determine how Mto1 localizes to the NE. Surprisingly, we find that Mto1, a constitutively cytoplasmic protein, docks at nuclear pore complexes (NPCs), via interaction with exportin Crm1 and cytoplasmic FG-nucleoporin Nup146. Although Mto1 is not a nuclear export cargo, it binds Crm1 via a nuclear export signal-like sequence, and docking requires both Ran in the GTP-bound state and Nup146 FG repeats. In addition to determining the mechanism of MTOC formation at the NE, our results reveal a novel role for Crm1 and the nuclear export machinery in the stable docking of a cytoplasmic protein complex at NPCs.
Data availability
The mass spectrometry proteomics data from both LFQ and SILAC experiments have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD008334
Article and author information
Author details
Funding
Wellcome (94517)
- Xun X Bao
- Eric M Lynch
- Kenneth E Sawin
Japan Society for the Promotion of Science (JP25116006)
- Tomoko Kojidani
- Tokuko Haraguchi
The Darwin Trust of Edinburgh
- Xun X Bao
Wellcome (108504)
- Christos Spanos
- Juri Rappsilber
Wellcome (91020)
- Christos Spanos
- Juri Rappsilber
Wellcome (203149)
- Xun X Bao
- Christos Spanos
- Eric M Lynch
- Juri Rappsilber
- Kenneth E Sawin
Japan Society for the Promotion of Science (JP17H03636)
- Tomoko Kojidani
- Tokuko Haraguchi
Japan Society for the Promotion of Science (JP17H01444)
- Yasushi Hiraoka
Japan Society for the Promotion of Science (JP16H01309)
- Yasushi Hiraoka
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2018, Bao et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 2,402
- views
-
- 411
- downloads
-
- 16
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
Further reading
-
- Cell Biology
Niemann–Pick disease type C (NPC) is a devastating lysosomal storage disease characterized by abnormal cholesterol accumulation in lysosomes. Currently, there is no treatment for NPC. Transcription factor EB (TFEB), a member of the microphthalmia transcription factors (MiTF), has emerged as a master regulator of lysosomal function and promoted the clearance of substrates stored in cells. However, it is not known whether TFEB plays a role in cholesterol clearance in NPC disease. Here, we show that transgenic overexpression of TFEB, but not TFE3 (another member of MiTF family) facilitates cholesterol clearance in various NPC1 cell models. Pharmacological activation of TFEB by sulforaphane (SFN), a previously identified natural small-molecule TFEB agonist by us, can dramatically ameliorate cholesterol accumulation in human and mouse NPC1 cell models. In NPC1 cells, SFN induces TFEB nuclear translocation via a ROS-Ca2+-calcineurin-dependent but MTOR-independent pathway and upregulates the expression of TFEB-downstream genes, promoting lysosomal exocytosis and biogenesis. While genetic inhibition of TFEB abolishes the cholesterol clearance and exocytosis effect by SFN. In the NPC1 mouse model, SFN dephosphorylates/activates TFEB in the brain and exhibits potent efficacy of rescuing the loss of Purkinje cells and body weight. Hence, pharmacological upregulating lysosome machinery via targeting TFEB represents a promising approach to treat NPC and related lysosomal storage diseases, and provides the possibility of TFEB agonists, that is, SFN as potential NPC therapeutic candidates.
-
- Cell Biology
- Developmental Biology
A study in mice reveals key interactions between proteins involved in fibroblast growth factor signaling and how they contribute to distinct stages of eye lens development.
