Compositions comprising a modified GIcNAc-1-phosphotransferase and methods of use thereof
The disclosure provides a modified UDP-GlcNAc:Lysosomal Enzyme GlcNAc phosphotransferase with enhanced ability to phosphorylate lysosomal enzymes and methods of use thereof.
1. A method to increase binding of a protein of interest to cell surface mannose 6-phosphate receptor (Man-6-P), the method comprising expressing a modified GlcNAc-1-PT α/β subunit in a cell, wherein the modified GlcNAc-1-PT α/β subunit comprises an internal deletion of amino acids with reference to full-length human GlnNAc-1-PT α/β subunit having the sequence of SEQ ID NO:1, wherein amino acids 86 to 322 and amino acids 438 to 928 are deleted, and wherein the increased binding of a protein of interest to cell surface mannose 6-phosphate receptor (Man-6-P) is compared to the binding of a protein of interest to cell surface mannose 6-phosphate receptor (Man-6-P) in a cell expressing endogenous GlcNAc-1-PT α/β subunit.
2. The method of claim 1 , wherein the protein of interest is a lysosomal protein.
3. The method of claim 2 , wherein the lysosomal protein is selected from the group consisting of β-glucocebrosidase (GBA), GalA, Cathepsin D (CathD), Niemann-Pick disease type C2 (NPC2), β-hexosaminidase (HEXB), α-Galactosidase (GLA), β-Mannosidase (MANBA), alpha-L-idurnoidase, iduronate sulfatase, arylsulfatase B, acid α-glucosidase (GAA), and lysosomal acid a mannosidase (LAMAN).
4. The method of claim 1 , wherein the protein of interest is a non-lysosomal protein.
5. The method of claim 4 , wherein the non-lysosomal protein is selected from the group consisting of DNaseI, Renin, leukemia inhibitory factor (LIF), protein O-fucosyltransferase 2 (PoFUT2), glycopepsinogen (GP), and the von Willebrand factor A1A2A3 domains.
6. The method of claim 1 , wherein the protein of interest is selected from the group consisting of the Pompe disease enzyme (acid a-glucosidase, GAA) and the alpha-mannosidosis enzyme (lysosomal acid a-mannosidase, LAMAN).
7. The method of claim 1 , wherein the amount of glycans with 2 Man-6-P residues is increased relative to GlcNAc-1-PT α/β subunit.
8. The method of claim 1 , wherein the phosphorylation of the protein of interest is enhanced.