Phosphatidylinositol-specific phospholipase

Zaikova, T. (2001). Synthesis of fluorogenic substrates for continuous assay of phosphatidylinositol-specific phospholipase C. Bioconjug. Chem. 12, 307-313. 

A bacterial phosphatidylinositol specific phospholipase C (PI-PLC) had been available for many years before it was demonstrated to strip a number of membrane-bound proteins from eukaryotic cell surfaces [1], Such proteins are anchored by a PI moiety in which the 6 position of inositol is glycosidically linked to glucosamine, which in turn is bonded to a polymannan backbone (Fig. 3-10). The polysaccharide chain is joined to the carboxyl terminal of the anchored protein via amide linkage to ethanolamine phosphate. The presence of a free NH2 group in the glucosamine residue makes the structure labile to nitrous acid. Bacterial PI-PLC hydrolyzes the bond between DAG and phosphati-dylinositols, releasing the water-soluble protein polysac charide-inositol phosphate moiety. These proteins are tethered by glycosylphosphatidylinositol (GPI) anchors. 

When the receptor interacts with its associated G protein, the conformation of the guanine-nucleotide-binding site is altered. The subunits then dissociate, and a phosphatidylinositol-specific phospholipase C (PI-PLC) is activated [5]. The subsequent hydrolysis of phosphatidylinositol bisphosphate then produces inositol triphosphate (IP3) and diacylglycerol (DAG), which are known to be secondary messengers. For example, the water soluble IP3 is released into the cell where its ultimate targets are the calcium storage organelles from which Ca2+ is released [3]. The presence of DAG in cells is known to activate the cellular enzyme protein kinase C (PKC) [6, 7], which phosphorylates a number of cellular... 

Neutrophil membranes contain inositol lipids, which comprise about 5-6% of the total membrane lipids. About 80% of these inositol lipids possess stearic acid (Cl8 0) at Cl and arachidonic acid (C20 4) at C2 positions. Phosphatidylinositol accounts for most of these lipids (90%), with smaller amounts of PIP (6%) and PIP 2 (4%), which are synthesised sequentially by the action of 4- and 5-specific kinases, respectively (see Fig. 6.6). Neutrophil membranes also possess a phosphatidylinositol-specific phospholipase C which cleaves phosphatidylinositol 4,5-bisphosphate (PIP2) into Ins 1,4,5 P3 and DAG (Fig. 6.7). Both PLC-/3(/ 2) and PLC-y (72) families appear to be present in neutrophils. The coupling of receptor occupancy to PLC activation in neutrophils can be through a heterotrimeric G-protein, the mobile subunit of which has been termed G p. Evidence for this G-protein link comes from the following facts ... 

Selected entries from Methods in Enzymology [vol, page(s)] Phosphatidylinositol-specific phospholipases C from Bacillus ce-reus and Bacillus thuringiensis, 197, 493 assays for phosphoinosi-tide-specific phospholipase C and purification of isozymes from bovine brain, 197, 502 properties of phospholipase C isozymes, 197, 511 phosphatidylinositol-specific phospholipase C from human platelets, 197, 518 purification of guinea pig uterus phos-phoinositide-specific phospholipase C, 197, 526. 

Akaterpin (372) is an inhibitor of phosphatidylinositol-specific phospholipase C from a Callyspongia sp. [326]. The relative stereochemistry of the ring junction in the upper decalin moiety of akaterpin was shown to be cis by synthesis of model compounds [327]. 

Smrcka, A. V., and Sternweis, P. C. (1993). Regulation of purified subtypes of phosphatidylinositol-specific phospholipase Cfl by G protein a and fig subunits. / Biol. Chem. 268, 9667-9674. 

Figure 2 Schematic model of the intracellular signaling mechanisms including phosphatidylinositol-specific phospholipase C (PI-PLC) isoforms, inositol-1,4,5-triphosphate (IP3) receptor, and protein kinase C (PKC) in the expression of delta opioid receptor agonist-induced spinal antinociception. In addition, PKC is considered to play a substantial role in an intracellular negative feedback action on the spinal delta opioid receptor-mediated antinociceptive pathway.

There is now considerable evidence to suggest that hormones which stimulate inositol phospholipid metabolism do so through a distinct G-protein [90-92]. It is thus possible that insulin might activate a G-protein in order to stimulate the proposed phosphatidylinositol-specific phospholipase C claimed to produce the GIPs insulin mediator (Fig. 4). 

Feng, J., Wehbi, H., and Roberts, M.F., 2002, Role of tryptophan residues in interfacial binding of phosphatidylinositol-specific phospholipase C.J.Biol. Chem. 277 19867-19875. 

Griffith, O.H., and Ryan, M., 1999, Bacterial phosphatidylinositol-specific phospholipase C Structure, function, and interaction with lipids. Biochim. Biophys. Acta 1441 237-254. 

Heinz, D.W., Ryan, M., Bullock, T.L., and Griffith, O.H., 1995, Crystal structure of the phosphatidylinositol-specific phospholipase C from Bacillus cereus in complex with myoinositol EMBOJ. 14 3855-3863. 

Sharom, F.J., and Lehto, M.T., 2002, Glycosylphosphatidylinositol-anchored proteins Structure, function, and cleavage by phosphatidylinositol-specific phospholipase C. Biochem. Cell. Biol. 80 535-549. 

Sibelius, U., Schulz, E.C., Rose, F., Hattar, K., Jacobs, T., Weiss, S., Chakraborty, T., Seeger, W., and Grimminger, F., 1999, Role of Listeria monocytogenes exotoxins listeriolysin and phosphatidylinositol-specific phospholipase C in activation of human neutrophils. Infect. Immun. 67 1125-1130... 

Hirayama, T., Ohto, C., Mizoguchi, T., and Shinozaki, K., 1995, A gene encoding a phosphatidylinositol-specific phospholipase C is induced by dehydration and salt stress in Arabidopsis thaliana. Proc. Natl. Acad. Sci. U.S.A. 92 3903-3907. 

W. D. Singer, H. A. Brown, and P. C. Stemweis. Regulation of eukaryotic phosphatidylinositol-specific phospholipase C and phospholipase D. Annu Rev Biochem, 66, 475-509, 1997. 

R. A. Mortara, L. M. Minelli, F. Vandekerckhove, V. Nussenzwieg, and F. J. Ramalho-Pinto, Phosphatidylinositol-specific phospholipase C (PI-PLC) cleavage of GPI-anchored surface molecules of Trypanosoma cruzi triggers in vitro morphological reorganization of trypomastigotes, J. Eukaryot. Microbiol., 48 (2002) 27-37. 

Netzer A, Gstraunthaler G (1993) Selective release of apical membrane enzymes from cultured renal epithelia by phosphatidylinositol-specific phospholipase C. Ren Physiol Biochem 16(6) 299-310... 

Davitz, M.A., Hereld, D., Shak, S., Krakow, J., Englund, P.T., and Nussen-zwEiG, V. A glycan-phosphatidylinositol-specific phospholipase D in human serum. Science, 1987, 238, 81-84. 

G. Muller, E.A. Dearey, A. Korndor-EER, and W. Bandlow, Stimulation of a glycosyl-phosphatidylinositol-specific phospholipase by insulin and the sulfonylurea, glimepiride, in rat adipocytes depends on increased glucose transport, J. Cell. Biol., 1994, 126, 1267-1276. 

Vanha-Perttula, T. and Kasurinen, J. (1989). Purification and characterization of phosphatidylinositol-specific phospholipase C from bovine spermatozoa. Int. J. Biochem. 27 997-1007. 

Figure 6.56 (b) Phosphatidylinositol-specific phospholipase C mechanism, shown... 

Bacterial phosphatidylinositol-specific phospholipase C (PI-PLC) (reviewed in ref. [51]) or trypanosomal GPI-specific phospholipase C (GPI-PLC) [52-54] releases GPI-anchored proteins from the cell surface leaving behind diacylglycerol. This cleavage not only solubilizes the protein, but also exposes a phosphoinositol-containing cryptic epitope termed cross-reacting determinant [55]. Reactivity of polyclonal antibodies derived against the cross-reacting determinant (CRD) provide additional evidence for the presence of a GPI anchor. 

Fig. 2. Enzymatic and chemical cleavage sites of GPI anchors useful in identifying GPI anchored membrane proteins. GPI-PLC, GPI-specific phospholipase C GPI-PLD, GPI-specific phospholipase D HF, hydrogen fluoride MONO, nitrous acid NaOH (NH3), mild alkali treatment PI-PLC, phosphatidylinositol-specific phospholipase C. (Redrawn from ref. [178].)...

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