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Functional link between R ab GTP ase‐mediated membrane trafficking and PI 4,5P 2 signaling
Author(s) -
Li Cuifang,
Kita Ayako,
Hashimoto Yuuka,
Ihara Misako,
Kato Ayaka,
Ogura Naoya,
Doi Akira,
Oku Masahide,
Itoh Toshiki,
Sakai Yasuyoshi,
Sugiura Reiko
Publication year - 2014
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1111/gtc.12123
Subject(s) - rab , biology , microbiology and biotechnology , gtpase , golgi apparatus , transport protein , signal transduction , cytoplasm , cytokinesis , vacuole , biochemistry , cell , endoplasmic reticulum , cell division
Fission yeast its3 + encodes an essential phosphatidylinositol‐4‐phosphate 5‐kinase ( PI 4P5 K ) that regulates cell integrity and cytokinesis. We performed a genetic screen to identify genes that function in PI 4P5 K ‐mediated signaling, and identified gyp10 + encoding a Rab GTP ase‐activating protein ( GAP ), a negative regulator for Rab GTP ase signaling. Its3 overproduction caused growth defects and abnormal cytoplasmic accumulation of the Its3 protein, which can be stained by calcofluor. Notably, Its3 overproducing cells displayed abnormal membranous structures, multilamella Golgi and fragmented vacuoles showed by Electron microscopy. Furthermore, the excess cytoplasmic Its3 structure partly colocalized with the fluorescence of FM 4‐64. Gyp10 rescued both growth defects and abnormal Its3 localization when it was over‐expressed. Gyp10 functionally interacted with the Rab GTP ases Ypt3 and Ryh1, both of which regulate Golgi membrane trafficking. Consistently, mutation or deletion of Ypt3 and Ryh1 suppressed phenotypes associated with Its3 overproduction. Importantly, the plasma membrane localization of Its3 was also affected by the impairment of the Ypt3/Ryh1 Rab membrane trafficking, thus suggesting that membrane trafficking events regulated by two Rab GTP ases functionally interacts with PI 4,5P 2 signaling. These results suggest a mechanism whereby PI 4P5K signaling/localization is affected by Golgi membrane trafficking, thus provide a functional link between the PI 4,5P 2 signaling and Rab‐mediated trafficking.