2012年9月
Sip1, a Conserved AP-1 Accessory Protein, Is Important for Golgi/Endosome Trafficking in Fission Yeast
PLOS ONE
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- 巻
- 7
- 号
- 9
- 開始ページ
- e45324
- 終了ページ
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1371/journal.pone.0045324
- 出版者・発行元
- PUBLIC LIBRARY SCIENCE
We had previously identified the mutant allele of apm1(+) that encodes a homolog of the mammalian mu 1A subunit of the clathrin-associated adaptor protein-1 (AP-1) complex and demonstrated that the AP-1 complex plays a role in Golgi/endosome trafficking, secretion, and vacuole fusion in fission yeast. Here, we isolated a mutant allele of its4(+)/sip1(+), which encodes a conserved AP-1 accessory protein. The its4-1/sip1-i4 mutants and apm1-deletion cells exhibited similar phenotypes, including sensitivity to the calcineurin inhibitor FK506, Cl- and valproic acid as well as various defects in Golgi/endosomal trafficking and cytokinesis. Electron micrographs of sip1-i4 mutants revealed vacuole fragmentation and accumulation of abnormal Golgi-like structures and secretory vesicles. Overexpression of Apm1 suppressed defective membrane trafficking in sip1-i4 mutants. The Sip1-green fluorescent protein (GFP) co-localized with Apm1-mCherry at Golgi/endosomes, and Sip1 physically interacted with each subunit of the AP-1 complex. We found that Sip1 was a Golgi/endosomal protein and the sip1-i4 mutation affected AP-1 localization at Golgi/endosomes, thus indicating that Sip1 recruited the AP-1 complex to endosomal membranes by physically interacting with each subunit of this complex. Furthermore, Sip1 is required for the correct localization of Bgs1/Cps1, 1,3-beta-D-glucan synthase to polarized growth sites. Consistently, the sip1-i4 mutants displayed a severe sensitivity to micafungin, a potent inhibitor of 1,3-beta-D-glucan synthase. Taken together, our findings reveal a role for Sip1 in the regulation of Golgi/endosome trafficking in coordination with the AP-1 complex, and identified Bgs1, required for cell wall synthesis, as the new cargo of AP-1-dependent trafficking.
- リンク情報
- ID情報
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- DOI : 10.1371/journal.pone.0045324
- ISSN : 1932-6203
- PubMed ID : 23028933
- Web of Science ID : WOS:000309742800051