Mannosidases capable of uncapping mannose-1-phospho-6-mannose linkages and demannosylating phosphorylated N-glycans and methods of facilitating mammalian cellular uptake of glycoproteins

1. A method for uncapping mannose-1-phospho-6-mannose moieties and demannosylating phosphorylated N-glycans on a glycoprotein, said method comprising:

a) providing said glycoprotein having phosphorylated N-glycans containing said mannose-1-phospho-6-mannose moiety; and

b) contacting said glycoprotein with a single mannosidase that (i) hydrolyzes a mannose-1-phospho-6-mannose moiety to mannose-6-phosphate and (ii) hydrolyzes terminal alpha-1,2 mannose, alpha-1,3 mannose, or alpha-1,6 mannose linkages, wherein said single mannosidase is a Jack Bean mannosidase,

wherein the method is performed in vitro.

2. The method of claim 1 , wherein said glycoprotein is a human protein.

3. The method of claim 1 , wherein said glycoprotein is a pathogen protein, a lysosomal protein, a growth factor, a cytokine, a chemokine, an antibody or antigen-binding fragment thereof, or a fusion protein.

4. The method of claim 3 , wherein said lysosomal protein is a lysosomal enzyme.

5. The method of claim 4 , wherein said lysosomal enzyme is acid alpha glucosidase or alpha galactosidase.

6. The method of claim 1 , wherein said glycoprotein is associated with a lysosomal storage disorder (LSD.

7. The method of claim 6 , wherein said LSD is Fabry's disease, mucopolysaccharidosis I, Farber disease, Gaucher disease, GM1-gangliosidosis, Tay-Sachs disease, Sandhoff disease, GM2 activator disease, Krabbe disease, metachromatic leukodystrophy, Niemann-Pick disease, Scheie disease, Hunter disease, Sanfilippo disease, Morquio disease, Maroteaux-Lamy disease, hyaluronidase deficiency, aspartylglucosaminuria, fucosidosis, mannosidosis, Schindler disease, sialidosis type 1, Pompe disease, Pycnodysostosis, ceroid lipofuscinosis, cholesterol ester storage disease, Wolman disease, Multiple sulfatase deficiency, galactosialidosis, mucolipidosis, cystinosis, sialic acid storage disorder, chylomicron retention disease with Marinesco-Sjögren syndrome, Hermansky-Pudlak syndrome, Chediak-Higashi syndrome, Danon disease, or Geleophysic dysplasia.

8. A method for uncapping mannose-1-phospho-6-mannose moieties and demannosylating phosphorylated N-glycans on a glycoprotein, said method comprising:

a) providing said glycoprotein having phosphorylated N-glycans containing said mannose-1-phospho-6-mannose moiety;

b) contacting said glycoprotein with a single mannosidase that (i) hydrolyzes a mannose-1-phospho-6-mannose moiety to mannose-6-phosphate and (ii) hydrolyzes terminal alpha-1,2 mannose, alpha-1,3 mannose, or alpha-1,6 mannose linkages, wherein said single mannosidase is a Jack Bean mannosidase; and

c) contacting a mammalian cell with said glycoprotein comprising said demannosylated phosphorylated N-glycans, wherein, after said contacting, said glycoprotein is transported to the interior of said mammalian cell,

wherein the method is performed in vitro.

9. The method of claim 8 , wherein said mammalian cell is a human cell.