Molecular Characterization, 3D Modeling of Grass Carp Autophagy Related 16 Protein Like 1 (ATG16L1)

Autophagy is a highly conserved homoeostatic mechanism, which plays a pivotal role in both metabolism and immune systems. Among autophagy related (ATG) proteins, ATG16L1 assists the formation of the phagophore and participates in the resistant of bacterial invasion in mammals. However, in grass carp (ctenopharyngodon idellus), one of the four major Chinese carps, the characterization of ATG16L1 remains to be defined. This paper described the cloning and characterization of grass carp ATG16L1 (gcATG16L1) and the 3D structure of its WD40-repeat domain was predicted. The CDS of gcATG16L1 consists of 1872 base pairs and encodes 624 amino acids with three conserved domains, a ATG5-binding domain, a coiled-coil domain (CCD), and a WD40-repeat domain. The phylogenetic analysis clusters gcATG16L1 with common carp but independently of the zebrafish homolog, since zebrafish ATG16L1 lacks WD40-repeat domain. The 3D structure of gcATG16L1 WD40-repeat domain was the first homology model of fish ATG16L1 and revealed a high similarity with the mammalian counterparts, which has been deduced to be involved in mediating interaction with several factors, such as ubiquitin and NOD-CARD, and regulating inflammatory response.