Autophagy: regulation and crosstalk with apoptosis

Tianfeng Lan

IMI CONFIDENTIAL www.xianimi.com 2

Overview

(1) de novo formation of a double-membrane bound structure or phagophore

(2) elongation of this lipid-based membrane

(3) Encapsulation(包裹） of intracellular cargo to form the mature autophagosome

An ancient process that is highly conserved among eukaryotes

IMI CONFIDENTIAL www.xianimi.com 3

Core MachineryMTOR （ mechanistic target of rapamycin）

MTOR is active in nutrient-rich conditions, inhibiting autophagy and protein degradation. When MTOR is inactivated by starvation conditions, dephosphorylated ULK1 dissociates from the MTOR complex and phosphorylates ATG13 and RB1CC1/FIP200

IMI CONFIDENTIAL www.xianimi.com 4

The PtdIns3K complex is assembled at the site of the nascent autophagosomal membrane. UVRAG and ATG14 are found in BECN1 complexes in a mutually exclusive manner

IMI CONFIDENTIAL www.xianimi.com 5

The two ubiquitin-like conjugation systems essential for membrane

elongation are outlined schematically.

IMI CONFIDENTIAL www.xianimi.com 6

The autophagosomal membrane (orange crescent) is studded with LC3–PE (stylized in black). The membrane elongation is dependent on the ATG12–ATG5-ATG16L1 conjugation system

Sources of Autophagosomal Membranes

Sources Evidences

endoplasmic reticulum immunostaining(PI3K, ATG14), electron microscopy

mitochondria flourescence microscopy(LC3, ATG5)

Golgi apparatus ATG9

plasma membrane PM SNAREs

Induction of autophay

nutrient status

hormonal regulation

hypoxia

heat sress

ROS

ER stress

UPR :unfold protein response

ATF6, ERN1/IRE1, EIF2AK3/PERK pathway

Autophagy

Types of Autophagy

Aggrephagy(聚集吞噬 )

Degrading proteins that are assembled into large protein aggregates

Aggresome requires K63 linked polyubiquitination to recruit autophagy receptors SQSTM1, NBR1 and WDFY3. These receptors provide a physical link to ATG8

Allophagy, crinophagy and zymophagy

Allophagy: degradation of paternally-derived mitochondriaupon fertilization in the zygote

Crinophagy(分泌吞噬） :secretory granules containing hormones are directly routed to lysosomes without contribution from autophagy

zymophagy(酶原吞噬 ):degradation of activated zymogen granules

Exophagy(分泌吞噬）

Nondegradative processes involved in protein secretion: IL-6, IL-8

Heterophagy and endosomal microautophagy

Heterophagy(异体吞噬 ): degradation extracellular material that has been internalized within the cell

Immunophagy(免疫吞噬 )

Type I: processing of foreign or endogenous immunologically active molecules. xenophagy, the autophagic activation of macrophages, pattern recognition receptor activation, MHC class II endogenous antigen presentation, and thymic selection

Type II: regulates cell viability and immune cell function. Specific roles for this type include: T/B cell homeostasis, T cell maturation and Paneth cell maintenance

Type III immunophagy utilizes specific ATG proteins to regulate immune signaling

Lipophagy(脂质吞噬 )the metabolic regulation of lipids through degradation of lipid dropl

ets (LDs) by autophagy

Mitophagy(线粒体自噬 )

Selective degradation of mitochondria through autophagy, although the process may be cell specific within mammals.

Nucleophagy(胞核自噬 )

mammalian cells can exhibit complete encapsulation of the nucleus

Pexophagy(过氧化物酶体自噬）selective degradation of peroxisomes through autophagy

Reticulophagy and ribophagy

Degradation of the ER through reticulophagy occurs in response to ER stress

Ribophagy, the selective elimination of free ribosomes in the cytosol, is also linked to the ER stress response similar to reticulophagy.

Xenophagy(异物自噬 )

Viruses, bacteria and parasites can be eliminatedin an autophagic process involved in innate immunity defense

termed xenophagy

Autophagy–Apoptosis Crosstalk

BECN1–BCL2 interaction

BCL2 acts as a BECN1 antagonist, through direct interaction with the BH3 domain found on BECN1, preventing activation of the PtdIns3K complex and induction of autophagy

BECN1–BCL2L11 interaction

Inactive BCL2L11 may act to repress BECN1 until autophagy is induced by nutrient deprivation

案例分析

拓步雄，中文，设计到撰写修改时间约 1周，首次投稿《中华高血压杂志》

修改意见较多，且非常注意实验的细节

二次修回，依然在抠细节！

退稿！

1.尊重服从专家审稿意见！

2.中华类文章对于实验方法，如分组，分组依据，处理时间要求较严格！

3.如果不明白编辑的意图，可以电话询问！