PtdIns(4,5)P2 signaling regulates ATG14 and autophagy.
Autophagy is a regulated self-digestion pathway with fundamental roles in cell homeostasis and diseases. Autophagy is regulated by coordinated actions of a series of autophagy-related (ATG) proteins. The Barkor/ATG14(L)-VPS34 (a class III phosphatidylinositol 3-kinase) complex and its product phosphatidylinositol 3-phosphate [PtdIns(3)P] play key roles in autophagy initiation. ATG14 contains a C-terminal Barkor/ATG14(L) autophagosome-targeting sequence (BATS) domain that senses the curvature of PtdIns(3)P-containing membrane. The BATS domain also strongly binds PtdIns(4,5)P2, but the functional significance has been unclear. Here we show that ATG14 specifically interacts with type Iγ PIP kinase isoform 5 (PIPKIγi5), an enzyme that generates PtdIns(4,5)P2 in mammalian cells. Autophagosomes have associated PIPKIγi5 and PtdIns(4,5)P2 that are colocalized with late endosomes and the endoplasmic reticulum. PtdIns(4,5)P2 generation at these sites requires PIPKIγi5. Loss of PIPKIγi5 results in a loss of ATG14, UV irradiation resistance-associated gene, and Beclin 1 and a block of autophagy. PtdIns(4,5)P2 binding to the ATG14-BATS domain regulates ATG14 interaction with VPS34 and Beclin 1, and thus plays a key role in ATG14 complex assembly and autophagy initiation. This study identifies an unexpected role for PtdIns(4,5)P2 signaling in the regulation of ATG14 complex and autophagy.
Program in Molecular and Cellular Pharmacology, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53706.
Xiaojun
0000-0003-3300-2240
X
Tan
Program in Molecular and Cellular Pharmacology, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53706.
Narendra
N
Thapa
Program in Molecular and Cellular Pharmacology, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53706.
Yihan
Y
Liao
Program in Molecular and Cellular Pharmacology, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53706.
Suyong
S
Choi
Program in Molecular and Cellular Pharmacology, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53706 raanders@wisc.edu.
Richard A
RA
Anderson
D033942:Adaptor Proteins, Vesicular Transport / Q000378:metabolism*; D001343:Autophagy; D000071187:Autophagy-Related Protein 5 / Q000378:metabolism; D000071183:Autophagy-Related Proteins / Q000378:metabolism*; D000071186:Beclin-1 / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D004721:Endoplasmic Reticulum / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D055785:Gene Knockdown Techniques; D006801:Humans; D009154:Mutation / Q000235:genetics; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor); D011485:Protein Binding; D000072417:Protein Domains; D015398:Signal Transduction; D013347:Subcellular Fractions / Q000378:metabolism
C539000:ATG14 protein, human; D033942:Adaptor Proteins, Vesicular Transport; D000071187:Autophagy-Related Protein 5; D000071183:Autophagy-Related Proteins; D000071186:Beclin-1; D002352:Carrier Proteins; D019269:Phosphatidylinositol 4,5-Diphosphate; C426003:ZFYVE1 protein, human; D017853:Phosphotransferases (Alcohol Group Acceptor)
ATG14; ATG14–BATS domain; PIPKIγi5; PtdIns(4,5)P2; autophagy