The effects on phosphoinositide metabolism of preincubation of platelets for 90 min with 10 mM-Li+ were studied. Measurements were made of [32P]phosphate-labelled phosphoinositides and of [3H]inositol-labelled inositol mono-, bis- and tris-phosphate (InsP, InsP2 and InsP3). Li+ had no effect on the basal radioactivity in the phosphoinositides or in InsP2 or InsP3, but it caused a 1.8-fold incre...

In pancreatic acinar cells, inositol 1,4,5-trisphosphate (InsP(3))-dependent cytosolic calcium ([Ca(2+)](i)) increases resulting from agonist stimulation are initiated in an apical "trigger zone," where the vast majority of InsP(3) receptors (InsP(3)R) are localized. At threshold stimulation, [Ca(2+)](i) signals are confined to this region, whereas at concentrations of agonists that optimally e...

Protein kinase CK2 is a ubiquitous protein kinase that can phosphorylate various proteins involved in central cellular processes, such as signal transduction, cell division, and proliferation. We have shown that the human nucleolar phosphoprotein p140 (hNopp140) is able to regulate the catalytic activity of CK2. Unphosphorylated hNopp140 and phospho-hNopp140 bind to the regulatory and catalytic...

We have previously found that for permeabilized L1210 cells, low micromolar concentrations of Ins(1,3,4,5)P % added prior to Ins(2,4,5)P $ enhance the effects of suboptimal concentrations of Ins(2,4,5)P $ in causing Ca#+ release from InsP $ -sensitive Ca#+ stores [Cullen, Irvine and Dawson (1990) Biochem. J. 271, 549–553]. If this was due either to some conversion of added Ins(1,3,4,5)P % into ...

Coordinated flight in winged insects requires rhythmic activity of the underlying neural circuit. Here, we show that Drosophila mutants for the inositol 1,4,5-trisphosphate (InsP(3)) receptor gene (itpr) are flightless. Electrophysiological recordings from thoracic indirect flight muscles show increased spontaneous firing accompanied by a loss of rhythmic flight activity patterns normally gener...

Spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph disease (MJD), is an autosomal-dominant neurodegenerative disorder caused by a polyglutamine expansion in ataxin-3 (ATX3; MJD1) protein. In biochemical experiments, we demonstrate that mutant ATX3(exp) specifically associated with the type 1 inositol 1,4,5-trisphosphate receptor (InsP(3)R1), an intracellular calcium (Ca(2+)) rel...

The effects of the muscarinic agonist carbachol, histamine and bradykinin on incorporation of [3H]inositol into the phosphoinositides and the formation of [3H]InsPs were examined in bovine tracheal smooth-muscle (BTSM) slices labelled with [3H]inositol. These agonists result in substantial and dose-related increases in the incorporation of [3H]inositol into the phospholipids. Carbachol and hist...

background: patients with primary sjögren’s syndrome (pss) produce functional igg against cholinoreceptor of exocrine glands modifying their activity. the aim of the present work was to demonstrate pss igg antibodies (pss igg) interacting with m 3 muscarinic acetylcholine receptors (machr) of rats submandibular glands that alter mucin release and production via phospholipase c (plc) and cycloox...

Intracellular calcium concentration ([Ca(2+)](i)) signals are central to the mechanisms underlying fluid and protein secretion in pancreatic and parotid acinar cells. Calcium release was studied in natively buffered cells following focal laser photolysis of caged molecules. Focal photolysis of caged-inositol 1,4,5 trisphosphate (InsP(3)) in the apical region resulted in Ca(2+) release from the ...

Background: Within-breath reactance from forced oscillometry estimates resistance via its inspiratory component (Xrs,insp) and flow limitation via its expiratory component (Xrs,exp). Aim: To assess whether reactance can detect recovery from an exacerbation of chronic obstructive pulmonary disease (COPD). Method: 39 subjects with a COPD exacerbation were assessed on three occasions over 6 weeks ...