Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2019

Erindi/veggspjald / Talk/poster E50

An isoform of ATG7 is unable to perform its characterized autophagy function

Höfundar / Authors: Sigridur S. Hlynsdottir (1), Kristrun Yr Holm (1), Kevin Ostacolo(1), Linda Sooman (1), Margret H. Ogmundsdottir (1)

Starfsvettvangur / Affiliations: 1. Biomedical center, School of Medicine, University of Iceland

Kynnir / Presenter: Sigridur S. Hlynsdottir

ATG7 is an important protein of the autophagy pathway, a degradation mechanism involved in cellular homeostasis. Through autophagy, cellular components are engulfed in an autophagosome, which subsequently fuses with a lysosome forming an autolysosome. The best characterized function of ATG7 is to facilitate the formation of the growing autophagosomal membrane by lipidating LC3/GABARAP proteins. Recently, the lab identified an ATG7 isoform which is unable to mediate this lipidation. The isoform ATG7(2) is missing an exon of 27 amino acids, essential for the binding of ATG7 to the LC3/GABARAP proteins.
Our aim is to characterize the protein expression of ATG7(2) in human tissues and subsequently its function. We used the GTEx, TARGET and TCGA databases to analyze the mRNA expression of ATG7(2) and found that it is ubiquitously expressed. It is generally expressed at a lower level than the full-length isoform, ATG7(1). However, ATG7(2) has a higher expression in blood compared to ATG7(1) and our preliminary data indicates a physiological role of the shorter isoform. We are furthermore using mass spectrometry analysis of protein interaction to dissect what that role might be.
ATG7 is a key protein of the autophagy pathway and it will be important to dissect out if and then which physiological role ATG7(2) has to further our understanding on the pathway. Characterizing the function of this short isoform could also prove a useful tool to study ATG7-independent autophagy.