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Gastric GATA‐6 DNA‐binding protein: proteolysis induced by cAMP
Author(s) -
Nakagawa Reiko,
Sato Ryuichiro,
Futai Masamitsu,
Yokosawa Hideyoshi,
Maeda Masatomo
Publication year - 1997
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(97)00443-2
Subject(s) - protein kinase a , proteasome , cytoplasm , microbiology and biotechnology , proteases , biology , proteolysis , autophagy related protein 13 , phosphorylation , gata2 , kinase , transcription factor , biochemistry , chemistry , protein phosphorylation , gene , enzyme
The rat gastric GATA DNA‐binding protein, GATA‐6 (GATA‐GT1), was stably expressed in CHO‐K1 cells. The GATA‐6 protein was localized in the nucleus but not in the cytoplasm. Interestingly, when cells were treated with dibutyryl cAMP, the GATA‐6 protein was specifically degraded. Such a phenomenon was not observed in the presence of 5′‐AMP or dibutyryl cGMP. The cellular level of the GATA‐6 protein was restored upon removal of dibutyryl cAMP. Degradation was also induced by cholera toxin, which increased the cellular cAMP concentration, and was inhibited by a protein kinase A inhibitor. However, activators of protein kinase C did not have any effect. The degradation was inhibited by proteasome inhibitors (PSI (benzyloxycarbonyl‐Ile‐Glu( O ‐ t ‐Bu)‐Ala‐leucinal) and MG115 (benzyloxycarbonyl‐Leu‐Leu‐norvalinal)) but not by those of lysosomes and serine proteases. These results suggest that a kinase‐mediated protein phosphorylation is the cellular signal for degradation of the GATA‐6 protein. This finding constitutes a novel aspect of regulation by GATA DNA‐binding proteins, which are essential for developmental processes and tissue‐specific transcription.