Microautophagy in the yeast vacuole depends on the activities of phosphatidylinositol 4-kinases, Stt4p and Pik1p

Kurokawa, Yuna; Konishi, Rikako; Yoshida, Akane; Tomioku, Kanna; Tanabe, Kenji; Fujita, Akikazu

doi:10.1016/j.bbamem.2020.183416

Cited by 11 publications

(13 citation statements)

References 48 publications

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“…Consistently, the PI4P appears exclusively in the cytosolic (inner) leaflet of the microautophagic bodies that accumulate in the vacuole lumen in both the stationary phase and during the acute nitrogen–carbon starvation [ 121 ]. The PI4P nanoclusters of the raft-like vacuolar microdomains play an important role in microautophagy, because the mutants of the yeast phosphatidylinositol 4-kinases (PI4Ks), Stt4 and Pik1, have much smaller number of microautophagic bodies in both the stationary phase and during the acute nitrogen–carbon starvation [ 121 ]. However, it is not clear if the PI4Ks affect the raft-like vacuolar domain formation.…”

Section: Lipid Droplet Turnovermentioning

confidence: 95%

“…Contrary to mammalian lipophagy, which can be induced by rapamycin [ 66 ], treatment with rapamycin fails to induce lipophagy in yeast [ 118 ]. However, it can be induced by numerous other ways, such as acute nitrogen starvation [ 34 , 89 ], carbon starvation (both acute [ 118 , 119 ] and gradual [ 33 , 89 , 120 ]), and acute nitrogen–carbon starvation combined [ 121 ]. To achieve acute nitrogen starvation, S. cerevisiae and K. phaffii cells are transferred to the medium without a source of nitrogen [ 34 , 89 ].…”

Section: Lipid Droplet Turnovermentioning

confidence: 99%

“…Stationary phase lipophagy can also be induced in K. phaffii without the fermentation of glucose to ethanol and diauxic shift [ 89 ]. Finally, acute nitrogen–carbon starvation is created by transferring the cells to the medium without both nitrogen and carbon sources [ 121 ].…”

Section: Lipid Droplet Turnovermentioning

confidence: 99%

Section: Lipid Droplet Turnovermentioning

confidence: 99%

“…Interestingly, the raft-like vacuolar microdomains contain the phosphatidylinositol 4-phosphate (PI4P) nanoclusters, and these clusters form only in the cytosolic leaflet of the vacuolar membrane that comes in direct contact with the cytosolic LDs in the stationary phase [ 121 , 134 ]. Consistently, the PI4P appears exclusively in the cytosolic (inner) leaflet of the microautophagic bodies that accumulate in the vacuole lumen in both the stationary phase and during the acute nitrogen–carbon starvation [ 121 ]. The PI4P nanoclusters of the raft-like vacuolar microdomains play an important role in microautophagy, because the mutants of the yeast phosphatidylinositol 4-kinases (PI4Ks), Stt4 and Pik1, have much smaller number of microautophagic bodies in both the stationary phase and during the acute nitrogen–carbon starvation [ 121 ].…”

Section: Lipid Droplet Turnovermentioning

confidence: 99%

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Lipid Droplets and Their Autophagic Turnover via the Raft-Like Vacuolar Microdomains

Rahman

Kumar

Sánchez

et al. 2021

IJMS

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Although once perceived as inert structures that merely serve for lipid storage, lipid droplets (LDs) have proven to be the dynamic organelles that hold many cellular functions. The LDs’ basic structure of a hydrophobic core consisting of neutral lipids and enclosed in a phospholipid monolayer allows for quick lipid accessibility for intracellular energy and membrane production. Whereas formed at the peripheral and perinuclear endoplasmic reticulum, LDs are degraded either in the cytosol by lipolysis or in the vacuoles/lysosomes by autophagy. Autophagy is a regulated breakdown of dysfunctional, damaged, or surplus cellular components. The selective autophagy of LDs is called lipophagy. Here, we review LDs and their degradation by lipophagy in yeast, which proceeds via the micrometer-scale raft-like lipid domains in the vacuolar membrane. These vacuolar microdomains form during nutrient deprivation and facilitate internalization of LDs via the vacuolar membrane invagination and scission. The resultant intra-vacuolar autophagic bodies with LDs inside are broken down by vacuolar lipases and proteases. This type of lipophagy is called microlipophagy as it resembles microautophagy, the type of autophagy when substrates are sequestered right at the surface of a lytic compartment. Yeast microlipophagy via the raft-like vacuolar microdomains is a great model system to study the role of lipid domains in microautophagic pathways.

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Section: Lipid Droplet Turnovermentioning

confidence: 95%

Section: Lipid Droplet Turnovermentioning

confidence: 99%

Section: Lipid Droplet Turnovermentioning

confidence: 99%

Section: Lipid Droplet Turnovermentioning

confidence: 99%

Section: Lipid Droplet Turnovermentioning

confidence: 99%

See 3 more Smart Citations

Lipid Droplets and Their Autophagic Turnover via the Raft-Like Vacuolar Microdomains

Rahman

Kumar

Sánchez

et al. 2021

IJMS

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Selective increment of phosphatidylserine on the autophagic body membrane in the yeast vacuole

et al. 2021

Self Cite

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In yeast cells, the autophagosome is a double‐membrane structure; the inner membrane becomes the autophagic body membrane in the vacuole. Vacuolar enzymes degrade the autophagic body. There is no critical information regarding its selective degradation. Using the electron microscopy method, distributions of four phospholipids were examined in the autophagosomal and autophagic body membranes upon autophagy induction. The labeling of phosphatidylserine (PtdSer) in the autophagic body membrane dramatically increased after it converted from the autophagosome, but remained low in the vacuolar membrane. PtdSer in the autophagic body membrane also increased in atg15∆ yeast. These results suggest that the selective increment of PtdSer in the autophagic body, but not the vacuolar, membrane, can explain the selective degradation of the autophagic membrane.

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Lipophagy pathways in yeast are controlled by their distinct modes of induction

Fairman

Ouimet

2022

Yeast

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Lipid droplet (LD) autophagy (lipophagy) is a recently discovered selective form of autophagy and is a pathway for LD catabolism. This ubiquitous process has been an ongoing area of research within the budding yeast, Saccharomyces cerevisiae. Yeast lipophagy phenotypically resembles microautophagy, although it has a distinct set of genetic requirements depending on the mode of induction. This review highlights the similarities and differences between different forms of yeast lipophagy and offers perspectives on how our knowledge of lipophagy in yeast may guide our understanding of this process within mammalian cells to ultimately inform future applications of lipophagy.

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Microautophagy in the yeast vacuole depends on the activities of phosphatidylinositol 4-kinases, Stt4p and Pik1p

Cited by 11 publications

References 48 publications

Lipid Droplets and Their Autophagic Turnover via the Raft-Like Vacuolar Microdomains

Lipid Droplets and Their Autophagic Turnover via the Raft-Like Vacuolar Microdomains

Selective increment of phosphatidylserine on the autophagic body membrane in the yeast vacuole

Lipophagy pathways in yeast are controlled by their distinct modes of induction

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