Mutations in the gene of human type IIb sodium-phosphate cotransporter SLC34A2

D S Lituiev,R G Kiyamova

doi:10.7124/bc.00013f

Abstract

Type IIb sodium-phosphate cotransporter (NaPi2b) provides phosphate intake in the cells of some epithelial tissues, osteoblasts and odontoblasts. Abnormal expression of NaPi2b has been detected in some types of epithelial tumors. An alteration in NaPi2b activity, caused by mutations in transporter gene SLC34A2, has been recently revealed in patients with pulmonary alveolar microlithiasis, an autosomal recessively inherited disease, characterized by deposition of calcium-phosphate precipitates in the lungs. In the present study we have combined the information about all mutations found to date in the coding sequence of SLC34A2 and its transcript, compiled their map, and analysed their relevance to the function of NaPi2b.

Highlights

Adequate phosphate absorption is an important process in the maintenance of metabolism at cellular and organism-wide levels
Mutations in the gene of NaPi2b (SLC34A) were identified by two independent research groups in patients with pulmonary alveolar microlithiasis (PAM), a rare hereditary autosomal recessive disease marked by calcium phosphate precipitate deposition in lungs
In order to consolidate current information and assess the possible role of NaPi2b polymorphism in cancer, we have performed analysis of mutations in the SLC34A2 gene published to date

Summary

Introduction

Adequate phosphate absorption is an important process in the maintenance of metabolism at cellular and organism-wide levels. MUTATIONS IN THE GENE OF HUMAN TYPE IIb SODIUM-PHOSPHATE COTRANSPORTER SLC34A2 occurring in the gene of NaPi2b in health and different pathologies. Recent studies have shown that the glycosylation of human NaPi2b is mostly N-linked [14] and six potential sites for N-glycosylation in the large extracellular loop (N294, N307, N312, N320, N334, N339 ) have been predicted [1, 2, 14]. The other member of this family transporters NaPi-IIa (type IIa sodium-phosphate cotransporter, NaPi2a), which is highly homologous to NaPi2b has only two consensus sites for Nglycosylation (N298 and N328) [1, 2] These data indicate that posttranslational protein modifications such as glycosylation could be important for transporters functioning. Mutations in the gene of NaPi2b (SLC34A) were identified by two independent research groups in patients with PAM, a rare hereditary autosomal recessive disease marked by calcium phosphate precipitate deposition in lungs. The authors hypothesized that phosphate transporter NaPi2b could be responsible for calci-

SNP database

Species Homo sapiens

Findings

Conclusion