Co-distribution of glycoconjugates and H+, K+- ATPase in the parietalcells of the greater horseshoe bat, Rhinolophus ferrumequinum (Schreber,1774)

Histochemical, lectin-histochemical, and immunohistochemical analyses were performed on parietal cells of the greater horseshoe bat, Rhinolophus ferrumequinum, to clarify the composition and distribution of oligosaccharide chains in the β-subunit of the protonic pump H+,K+-ATPase. PAS, Alcian Blue (pH 2.5) and Alcian Blue (pH 1.0) stainings detected only neutral glycoconjugates. Lectin-binding analyses included LTA, UEA-I, ConA, SBA, BSI-B4, AAA, DBA, PNA, and WGA. WGAand PNA-bindings were also tested after β-elimination to detect O-linked glycans. Parietal cells were negative for binding to LTA and UEA-I, and to PNA and WGA after β-elimination, indicating the lack of (1,2) fucosylated residues and of N-linked glycans, respectively. Immunohistochemical tests with anti-α- and anti-β-H+,K+-ATPase were positive. Two alternative patterns of glycoconjugate distribution were found, i.e. a perinuclear and a diffuse one, indicating localization in the intracellular canaliculus and in the tubulovesicular system of the parietal cells, respectively. Both the subunits of the H+,K+-ATPase and the galactosyl/galactosaminyl residues were co-distributed in both the perinuclear and the diffuse patterns, suggesting that the residues are part of the protonic pump. Glycosyl/glycosaminyl and mannosyl groups were concentrated in the tubulovesicular system, and fucosylated residues were found almost exclusively in the intracellular canaliculi; thus they are probably not included in the oligosaccharide chains of β-H+,K+-ATPase. These findings indicate that the oligosaccharide chains linked to the β-H+,K+-ATPase subunit in R. ferrumequinum have distinct features compared to the other mammals studied and confirms the taxon specificity of the chains in the proton pump