GABARAPL1 Summary

GABARAPL1 (gamma-aminobutyric acid receptor-associated protein-like 1) is a ubiquitin-like modifier protein that regulates intracellular trafficking and autophagy. It facilitates cell-surface expression of kappa-type opioid receptors through anterograde trafficking and participates in autophagosome formation, particularly in the maturation stage of autophagy. Through interaction with reticulophagy receptor TEX264, GABARAPL1 also contributes to endoplasmic reticulum remodeling and turnover under nutrient stress conditions (UniProt: Q9H0R8).

GABARAPL1 belongs to the GABARAP/GATE-16 subfamily of autophagy-related proteins, with roles extending beyond classical autophagy into specialized membrane trafficking pathways. While no baseline disease associations are annotated in UniProt, the protein's involvement in autophagy and cellular homeostasis positions it within pathways relevant to neurodegenerative processes.

In Alzheimer's disease, GABARAPL1 is significantly downregulated in post-mortem brain tissue relative to age-matched controls (Chaparral AD proteomics). Across subcellular fractions analyzed by quantitative mass spectrometry, the protein showed a mean log2 fold-change of −0.29, indicating reduced abundance in AD brain. This downregulation may reflect impaired autophagy and protein quality control mechanisms characteristic of AD pathology.