A full length cDNA clone encoding the precursor of the rat liver mitochondrial phosphate transporter (H+/P(i) symporter) has been isolated from a cDNA library using a bovine heart partial length phosphate transporter clone as a hybridization probe. The entire clone is 1263 base pairs in length with 5'- and 3'-untranslated regions of 16 and 168 base pairs, respectively. The open reading frame encodes for the mature protein (312 amino acids) preceded by a presequence of 44 amino acids enriched in basic residues. The polypeptide sequence predicted from the DNA sequence was confirmed by analyzing the first 17 amino-terminal amino acids of the pure phosphate transporter protein. The rat liver phosphate transporter differs from the bovine heart transporter in 32 amino acids (i.e. ~10%). It contains a region from amino acid 139 to 159 which is 37% identical with the β-subunit of the liver mitochondrial ATP synthase. Amino acid sequence comparisons of the P(i) transporter with P(i) binding proteins, other H+-linked symporters, and the human glucose transporter did not reveal significant sequence homology. Analysis of genomic DNA from both rat and S. cerevisiae by Southern blots using the rat liver mitochondrial P(i) carrier cDNA as a probe revealed remarkably similar restriction patterns, a finding consistent with the presence in lower and higher eukaryotes of homologous P(i) carrier proteins. This is the first report of the isolation, sequencing, and characterization of a full length cDNA coding for a protein involved in energy-coupled P(i) transport.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of Biological Chemistry|
|State||Published - Jan 1 1989|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology