Phospholipase B Domain Containing Protein 2 (PLBD2)

Most soluble lysosomal proteins carry Man6P (mannose 6-phosphate), a specific carbohydrate marker that enables their binding to cellular MPRs (Man6P receptors) and their subsequent targeting towards the lysosome.

This characteristic was exploited to identify novel soluble lysosomal proteins by proteomic analysis of Man6P proteins purified from a human cell line. The presence of Man6P sugars was confirmed by an MPR overlay experiment, which showed the direct and Man6P-dependent interaction between p76 and the MPR. The presence of six N-glycosylation sites was validated by progressive peptide-N-glycosidase F deglycosylation. Experiments using N- and C-termini directed anti-p76 antibodies provided insights into p76 maturation.