Gamma-aminobutyric acid (GABA) receptor-associated protein-like 1, also known as GABARAPL1, belongs to the MAP1 LC3 family. It increases cell surface expression of kappa type opioid receptor through facilitating anterograde intracellular trafficking of the receptor. Recombinant human GABARAPL1 protein was expressed in E.coli and purified by using conventional chromatography techniques.