cGMP-dependent protein kinase I beta physically and functionally interacts with the transcriptional regulator TFII-I.
Transcriptional regulation of the fos promoter by nitric oxide and cGMP can occur by nuclear translocation of cGMP-dependent protein kinase I (G-kinase I) (Gudi, T., Lohmann, S. M., and Pilz, R. B. (1997) Mol. Cell. Biol. 17, 5244-5254). To identify nuclear targets of G-kinase I, we performed a yeast two-hybrid screen with G-kinase I beta as bait. We found that G-kinase I beta interacted specifically with TFII-I, an unusual transcriptional regulator that associates with multiple proteins to modulate both basal and signal-induced transcription. By using purified recombinant proteins, the interaction was mapped to the N-terminal 93 amino acids of G-kinase I beta and one of six 95-amino acid repeats found in TFII-I. In baby hamster kidney cells, cGMP analogs enhanced co-immunoprecipitation of G-kinase I beta and TFII-I by inducing co-localization of both proteins in the nucleus, but in other cell types containing cytoplasmic TFII-I the G-kinase-TFII-I interaction was largely cGMP-independent. G-kinase phosphorylated TFII-I in vitro and in vivo on Ser(371) and Ser(743) outside of the interaction domain. G-kinase strongly enhanced TFII-I transactivation of a serum-response element-containing promoter in COS7 cells, and this effect was lost when Ser(371) and Ser(743) of TFII-I were mutated. TFII-I by itself had little effect on a full-length fos promoter in baby hamster kidney cells, but it synergistically enhanced transcriptional activation by G-kinase I beta. Binding of G-kinase to TFII-I may position the kinase to phosphorylate and regulate TFII-I and/or factors that interact with TFII-I at the serum-response element.
Casteel
Darren E
DE
Department of Medicine and Cancer Center, University of California, San Diego, La Jolla, California 92093-0652, USA.
Zhuang
Shunhui
S
Gudi
Tanima
T
Tang
Julian
J
Vuica
Milena
M
Desiderio
Stephen
S
Pilz
Renate B
RB
D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D017869:Cyclic GMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D016762:Genes, fos; D005982:Glutathione Transferase / Q000235:genetics; D006801:Humans; D016297:Mutagenesis, Site-Directed; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D017931:DNA Primers; D004268:DNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D005982:Glutathione Transferase; D017869:Cyclic GMP-Dependent Protein Kinases