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Depletion of mboa‐7 , an enzyme that incorporates polyunsaturated fatty acids into phosphatidylinositol ( PI ), impairs PI 3‐phosphate signaling in C aenorhabditis elegans
Author(s) -
Lee HyeonCheol,
Kubo Takuya,
Kono Nozomu,
KageNakadai Eriko,
GengyoAndo Keiko,
Mitani Shohei,
Inoue Takao,
Arai Hiroyuki
Publication year - 2012
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/j.1365-2443.2012.01624.x
Subject(s) - phosphatidylinositol , biology , pi , caenorhabditis elegans , mutant , gene knockdown , biochemistry , kinase , phosphatase , acyltransferase , diacylglycerol kinase , phosphatidic acid , microbiology and biotechnology , gene , enzyme , phospholipid , protein kinase c , membrane
Phosphatidylinositol ( PI ) is a constituent of biomembranes and a precursor of all phosphoinositides ( PIP s). A prominent characteristic of PI is that its sn ‐2 position is highly enriched in polyunsaturated fatty acids ( PUFA s), such as arachidonic acid or eicosapentaenoic acid. However, the biological significance of PUFA ‐containing PI remains unknown. We previously identified C aenorhabditis elegans ( C . elegans ) mboa‐7 as an acyltransferase that incorporates PUFA s into the sn ‐2 position of PI . In this study, we performed an RNA i enhancer screen against PI kinases and phosphatases using mboa‐7 mutants that have a reduced PUFA content in PI . Among the genes tested, knockdown of vps‐34 , a catalytic subunit of class III PI 3‐kinase that produces PI 3‐phosphate (PI3P) from PI , caused severe growth defects in mboa‐7 mutants. In both vps‐34 RNA i‐treated wild‐type worms and mboa‐7 mutants, the size of PI 3P‐positive early endosomes was significantly decreased. We also performed an RNA i enhancer screen against PI 3P‐related genes and found that, like knockdown of vps‐34 , knockdown of autophagy‐related genes caused severe growth defects in mboa‐7 mutants. Finally, we showed that autophagic clearance of protein aggregates is impaired in mboa‐7 mutants. Taken together, these results suggest that the PUFA chain in PI has a role in some PI 3 P signaling.