Premium
Identification, characterization, and molecular cloning of a novel transporter‐like protein localized to the central nervous system
Author(s) -
Gingrich Jay A.,
Andersen Peter H.,
Tiberi Mario,
Mestikawy Salah El,
Jorgensen Per N.,
Fremeau Robert T.,
Caron Marc G.
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)80917-6
Subject(s) - biology , biochemistry , complementary dna , signal peptide , northern blot , peptide sequence , microbiology and biotechnology , transmembrane protein , receptor , gene
During the course of large scale purification of the D 1 dopamine receptor from a rat brain, a protein of∼87,000 daltons (p87) was observed to copurify with the D 1 receptor through four chromatographic steps. To characterize the nature of this protein, bovine and rat cDNA clones were isolated and sequenced. The bovine and rat clones were highly conserved (98.5% identity). Each clone possessed an open reading frame of 2225 base pairs encoding a protein or 742 amino acids (calculated MW of 82,500), containing three stretches of peptide sequence obtained from p87 sequence analysis. Comparison of the deduced peptide sequence of this protein with those found in available databanks revealed that it was a novel protein related to the family of nutrient transport proteins from eukaryotes and bacteria, including, the mammalian facilitated glucose transporters, the yeast transporters for maltose, lactose, and glucose, and the proton‐driven bacterial transporters for arabinose, xylose, and citrate. In addition p87 also shares with these transporters a similar hydropathicity profile that suggests the presence of 12 transmembrane segments. The mRNA for p87 appears to be localized primarily, if not exclusively, to the central nervous system. Northern blot analysis reveals a message of ∼4.8 kb in cortex. hippocampus, brain stem, and cerebellum, but no detectable signal in peripheral tissues such as spleen, liver, kidney, lung, heart, or skeletal muscle. Evidence from Western blot analysis and immunohistochemistry suggests that this protein may be expressed in intracellular organelles or the membrane of synaptosomes rather than plasma membrane. Based on its structure and properties, p87 appears to define a new class transporter‐like proteins.