Characterization of the gene EPAC2: Structure, chromosomal localization, tissue expression, and identification of the liver-specific isoform

Citation
H. Ueno et al., Characterization of the gene EPAC2: Structure, chromosomal localization, tissue expression, and identification of the liver-specific isoform, GENOMICS, 78(1-2), 2001, pp. 91-98
Citations number
25
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Molecular Biology & Genetics
Journal title
GENOMICS
ISSN journal
0888-7543 → ACNP
Volume
78
Issue
1-2
Year of publication
2001
Pages
91 - 98
Database
ISI
SICI code
0888-7543(200111)78:1-2<91:COTGES>2.0.ZU;2-L
Abstract
The liver-specific protein cAMP-GEFII (also known as Epac2) belongs to a fa mily of cyclic adenosine monophosphate (cAMP) binding proteins having guani ne nucleotide exchange factor (GEF) activity (the cAMP-GEF family). Here we clone the gene EPAC2, encoding cAMP-GEFII, from a human liver cDNA library . Human EPAC2 has at least 31 exons and is mapped to human chromosome 2q31. Analyses by primer extension, reverse transcriptase-polymerase chain react ion, and in situ hybridization revealed the presence of three transcription start sites of liver-specific Epac2: two major sites! located in exon 10 a nd a minor site in intron 9. The same translation start site is used in all three transcripts. Liver-specific cAMP-GEFII protein, which lacks the firs t cAMP-binding domain and the Dishevelled/Eg1-10/Pleckstrin domain, was det ected at 79 kDa by immunoblot analysis, confirming the presence of the shor t form of cAMP-GEFII in the liver. Liver-specific cAMP-GEFII also has GEF a ctivity toward Rap1. These results demonstrate the presence of liver-specif ic cAMP-GEFII Together with the previous finding that cAMP-GEFII is respons ible for cAMP-dependent exocytosis in secretory cells, our study suggests t hat cAMP-GEFII may have a distinct role in liver.