Prophylactic treatment with D-myo-inositol 1,4,5-trisphosphate hexasodium [D-myo-Ins(1,4,5)P3], the sodium salt of the endogenous second messenger Ins(1,4,5)P3, triggers a reduction of infarct size comparable in magnitude to that seen with ischemic preconditioning (PC). However, the mechanisms underlying D-myo-Ins(1,4,5)P3-induced protection are unknown. Accordingly, our aim was to investigate ...

Generation of a phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P3] gradient within the plasma membrane is important for cell polarization and chemotaxis in many eukaryotic cells. The gradient is produced by the combined activity of phosphatidylinositol 3-kinase (PI3K) to increase PI(3,4,5)P3 on the membrane nearest the polarizing signal and PI(3,4,5)P3 dephosphorylation by phosphatase and t...

In this article, yeast two-hybrid system (YTHS) and bimolecular fluorescence complementation (BiFC) were used to analyze the interactions of cucurbit aphid-borne yellows virus (CABYV)-encoded proteins. P0, P1, P1-2, P3, P4, and P5 were tested by YTHS in all possible pairwise combinations, and only P3/P3 interaction was detected. Results obtained by BiFC further confirmed the self-interaction of...

The phage phi 29 protein p2, required for the formation of the protein p3-dAMP initiation complex, has been purified from Escherichia coli cells harboring a gene 2-containing recombinant plasmid. The purified protein p2, of molecular weight 68,000, had a specific DNA polymerase activity that elongated the p3-dAMP initiation complex when phi 29 DNA-protein p3 was used as template. In addition, t...

Permeabilized rat hepatocytes were used to study the effects of inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) and GTP on Ca2+ uptake and release by ATP-dependent intracellular Ca2+ storage pools. Under conditions where these Ca2+ pools were completely filled, maximal doses of Ins(1,4,5)P3 released only 25-30% of the sequestered Ca2+. The residual Ca2+ was freely releasable with the Ca2+ ionophore...

ADP-ribosylation factors (ARFs) are small GTP-binding proteins that are regulators of vesicle trafficking in eukaryotic cells. GRP1 is a member of a family of ARF guanine-nucleotide-exchange factors that binds in vitro the lipid second messenger phosphatidylinositol 3,4, 5-trisphosphate [PtdIns(3,4,5)P3]. In order to study the effects of PtdIns(3,4,5)P3 on the function of GRP1, we have cloned t...

C. reinhardtii sheds its flagella in response to acidification. Previously, we showed correlations between pH shock, deflagellation, and inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] production, but 100% of cells deflagellated by 5 s, which was the earliest that Ins(1,4,5)P3 accumulation could be accurately measured by techniques available to us at that time (Quarmby, L. M., Y. G. Yueh, J. L. Che...

The human insulin-like growth factor II (IGF-II) gene contains four promoters that are differentially active during cell growth and development. Promoter 3 (P3) is the most active promoter in fetal and non-hepatic adult tissues. In addition to its expression during development, P3 is also the major promoter in many tumour tissues and IGF-II-expressing cell lines. Here we show that AP-2 has a du...

Angiotensin II (AII) evokes a biphasic increase in inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) levels in adrenal glomerulosa cells, with an extracellular Ca(2+)-independent early peak followed by a secondary sustained elevation that is highly dependent on the presence of extracellular Ca2+. The Ca(2+)-dependent sustained phase of agonist-induced Ins(1,4,5)P3 production was closely correlated wi...

Executive dysfunction in fragile X-associated tremor/ataxia syndrome (FXTAS) has been suggested to mediate other cognitive impairments. In the present study, event-related potentials and neuropsychological testing were combined to investigate the brain mechanisms underlying the executive dysfunction in FXTAS. Thirty-two-channel electroencephalography was recorded during an auditory "oddball" ta...