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Differential influence of cAMP on the expression of the three subtypes (ATA1, ATA2, and ATA3) of the amino acid transport system A
Author(s) -
Hatanaka Takahiro,
Huang Wei,
Martindale Robert G.,
Ganapathy Vadivel
Publication year - 2001
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/s0014-5793(01)02848-4
Subject(s) - forskolin , cycloheximide , stimulation , cholera toxin , isobutyric acid , messenger rna , protein kinase a , biology , chemistry , microbiology and biotechnology , medicine , endocrinology , kinase , biochemistry , protein biosynthesis , gene
Treatment of HepG2 cells with forskolin led to 60–100% stimulation of system A activity, measured as the Na + ‐dependent uptake of α‐(methylamino)isobutyric acid. The stimulation was reproducible with cholera toxin and dibutyryl cAMP, and inhibitable by H7, a non‐specific protein kinase inhibitor. The stimulatory effect was eliminated by cycloheximide and actinomycin D. The forskolin effect was associated with an increase in the maximal velocity of the transport system, with no change in substrate affinity. These cells express three different subtypes of system A (ATA1, ATA2, and ATA3). Treatment with forskolin increased the steady‐state levels of ATA1 and ATA2 mRNAs, but decreased that of ATA3 mRNA.