ATG16L1-gene

The protein encoded by this gene is part of a large protein complex that is required for autophagy. In this context, autophagy refers to an important process in which protein components resulting from intracellular metabolism (cellular waste) are degraded in lysosomes (Lacher M et al. 1992).

ATG 16L1 is the most important gene regulating the autophagy pathway (see also other autophagy genes). This relates to the major process of autophagy in which accumulated intracellular "load" is translocated to lysosomes for degradation. Several transcript variants have been found for this gene, coding for different isoforms.

Autophagy is a process by which cells degrade and recycle damaged organelles or misfolded proteins. This accumulated "cellular waste" is encased and neutralized by a double membrane structure, the autophagosome. The autophagosome thus loaded fuses in a second step with a functional lysosome to form the autophagolysosome. In this cell vesicle, the cellular waste is enzymatically degraded.

This complex process requires the concerted processing of an extensive network of proteins. One of the early steps in autophagosome assembly is the formation of the large multimeric ATG12-ATG5-ATG16 complex. This protein complex acts as a ligase in the processing of ATG8. ATG8 is then incorporated into the expanding autophagosomal membrane and facilitates recruitment of the nuclear autophagy machinery and substrates destined for degradation.

Defects in the ATG16L1 gene are associated with inflammatory bowel diseases, such as Crohn's disease (Hampe J et al. 2007). ATG16L1 inhibits the NOD1- and NOD2-driven inflammatory cytokine response. Furthermore, the protein plays a role in regulating Paneth cell morphology and function. In an Iranian study, a significant association was found between the single nucleotide polymorphism rs2241879 on the ATG 16L1 gene and an increased risk of inflammatory bowel disease ( IBD ) in an Iranian population (Baradaran Ghavami S et al. 2019).

Remarkably, ATG 16L1 overexpression is associated with a more aggressive phenotype in oral squamous cell carcinoma (OSCC). ATG 16L1 could be used as a biomarker for selecting OSCC patients with a more aggressive phenotype (Tang JY et al 2015).

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4. Hampe J et al (2007) A genome-wide association scan of nonsynonymous SNPs identifies a susceptibility variant for Crohn disease in ATG16L1 Nature genetics 39:207-211.

5. Kanda T et al. (2021) Autophagy-related 16-like 1 is influenced by human herpes virus 1-encoded microRNAs in biopsy samples from the lower esophageal sphincter muscle during per-oral endoscopic myotomy for esophageal achalasia. Biomed Rep14:7.

6. Lacher M et al. (1992) Autophagy 16-like 1 rs 2241880 G allele is associated with Crohn's disease in German children. Acta paediatrica 98:1835-1840.

7. Tang JY et al (2015) Overexpression of autophagy-related 16-like 1 in patients with oral squamous cell carcinoma. Pathol Oncol Res 21:301-305.
8. Weersma RK et al (2008) ATG16L1 and IL23R are associated with inflammatory bowel diseases but not with celiac disease in the Netherlands. The American journal of gastroenterology 58:388-395.