PubMed · 8856469
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
M R Rosen. 1996. T wave memory.. https://doi.org/10.1111/j.1540-8167.1996.tb00587.x
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
We have previously reported that the binding of type I collagen to its receptor initiates platelet aggregation involving phosphoprotein phosphatase 1 (PP 1), which coprecipitates with the 65-kDa platelet type I collagen receptor. Phosphorylation of the anti-PP1 precipitation PP1 decreases its enzyme activity. In the present investigation, the mechanism of the decreased enzyme activity was studied by examining the phosphorylation of PP 1 on serine/threonine or tyrosine residues. Phosphoamino acid analysis of the PP 1 indicates that serine, threonine, and tyrosine can all be phosphorylated. We find that the activity of PP 1 decreases with serine/threonine phosphorylation but that phosphorylation of tyrosine residue activates enzyme activity. These results indicate that the activity of platelet phosphoprotein phosphatase 1 is controlled by phosphorylation and dephosphorylation states at multiple, different site(s).
The three yeast A kinase catalytic subunit isoforms are redundant for viability. We demonstrate that they have dramatically different roles in pseudohyphal development: Tpk2 is essential, whereas Tpk3 inhibits. Tpk1 has no discernible effect. Two-hybrid analysis identified the transcription factor Sfl1 as a protein that interacts specifically with Tpk2, but not Tpk1 or Tpk3. Deletion of SFL1 enhances pseudohyphal and invasive growth. Flo11, a cell surface flocculin required for pseudohyphal development, is transcriptionally regulated by Tpk2 and Sfl1. Genetic evidence indicates that Tpk2 acts upstream of Sfl1 in the regulation of Flo11.
Binding of hepatocyte growth factor (HGF) to its receptor Met induces autophosphorylation and activation of the tyrosine kinase activity. In HGF-treated HepG2 cells, we studied: (i) the expression patterns of early (c-myc, c-jun, and c-fos) and delayed-early (ornithine decarboxylase and c-met) response genes and (ii) the possible involvement of protein kinase transducers in the control of the expression of c-met and of other genes eventually induced downstream. c-met and c-myc mRNAs peaked 1-2 h after HGF, while c-jun and c-fos mRNAs slightly increased at 1 h. Ornithine decarboxylase activity was induced earlier (4 h) than the mRNA (8-10 h). The transducers involved in HGF-triggered gene inductions were investigated using different protein kinase inhibitors: genistein for the receptor tyrosine kinase, herbimycin A for the nonreceptor tyrosine kinase (pp60(c-src)), wortmannin for phosphatidylinositol 3-kinase (PI3K) and H7 for protein kinase C (PKC). The similarity of responses to PKC inhibition led to suppose that c-myc and ornithine decarboxylase mRNAs were induced sequentially along the same transduction pathway triggered by HGF. Ornithine decarboxylase activity seemed to be largely regulated by phosphorylation(s). The mRNA expression of c-jun was likely to undergo a negative regulation through a mechanism involving PI3K, while that of c-met seemed to be almost independent from various protein kinases (PI3K, pp60(c-src), and PKC).