Björn Storck: "Role of the Ulk1-Atg13-FIP200-Atg101 Complex in the Regulation of Autophagy: Crosstalk, Shortcuts, and Feedbacks"

Björn Storck
University Hospital Düsseldorf, Germany

Role of the Ulk1-Atg13-FIP200-Atg101 Complex in the Regulation of Autophagy: Crosstalk, Shortcuts, and Feedbacks

(Macro-)Autophagy is an evolutionary extremely conserved process, and the morphologic identification of autophagy was reported in the 1960s. Autophagy is a degradative process in which cytoplasmic components are sequestered by double-membraned vesicles called autophagosomes and subsequently delivered to lysosomes. Generally, autophagy is induced when cells are deprived of nutrients in order to maintain the amino acid pool. However, different alternative physiological roles have been proposed for autophagy, i.e. intracellular quality control, cell death, or tumour suppression. The Ulk1-Atg13-FIP200-Atg101 complex is a central mediator of autophagic processes. If nutrients are sufficiently available, the mammalian target of rapamycin complex 1 (mTORC1) associates with the Ulk1-Atg13-FIP200-Atg101 complex, leading to the phosphorylation of Ulk1 and Atg13, and to the inhibition of autophagy. In contrast, rapamycin treatment or starvation lead to the dissociation of mTORC1 from the Ulk1-Atg13-FIP200-Atg101 complex, resulting in a dephosphorylated status of Ulk1 and Atg13. This in turn leads to Ulk1 autophosphorylation and Ulk1-mediated phosphorylation of Atg13 and FIP200. These phosphorylations ultimately trigger the induction of autophagy. Here, an overview about our recent work on the Ulk1-Atg13-FIP200-Atg101 complex will be presented, including the identification of an Ulk1-dependent negative feedback signaling circuit and the characterization of Ulk1-independent induction of autophagy.