Title : Characterization of nucleotide pyrophosphatase-5 as an oligomannosidic
glycoprotein in rat brain
Abstract :
- Membrane glycoproteins of neural cells play crucial roles in axon guidance, synaptogenesis, and neuronal transmission
- We have here characterized membrane glycoproteins containing terminal alpha-mannose residues residues in rat brain membranes
- Affinity purification using Galanthus nivalis agglutinin , that is highly specific for terminal alpha-mannose residues, revealed a 50-kDa protein as well as 80-kDa SHPS-1 and 45-kDa beta2 subunit of Na,K-ATPase in rat brain membranes
- Combination of N-terminal peptide sequencing and mass spectrometry indicated that the 50-kDa protein was rat nucleotide pyrophosphatase-5 (NPP-5 )
- In contrast to other NPPs , NPP-5 was a type-I transmembrane protein
- Northern blot analysis showed that NPP-5 was highly expressed in brain, but also expressed in other peripheral tissues
- However, we could not detect either the NPP activity or the lysophospholipase D activity in the immunoprecipitates with antibodies to NPP-5 from rat brain membranes
- These data, therefore, suggest that NPP-5 is a neural oligomannosidic glycoprotein that may participate in neural cell communications