Cloning, sequencing, expression, and Gq-independent activation of phospholipase C-beta 2.

Park, D. J.; Jhon, Deok-Young; Kriz, Ronald; Knopf, John L.; Rhee, Sue Goo

doi:10.1016/s0021-9258(18)41963-1

Cited by 167 publications

(14 citation statements)

References 46 publications

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“…In comparison with the other classes of PLC isoenzymes, the hallmark features of the PLC-β family are a short region of " 80 amino acids between the X and Y regions which, in the case of the mammalian PLC-β isoenzymes contains up to ten consecutive negatively-charged amino acids, and an extended C-terminus of " 400 amino acids containing regions with a marked enrichment (approx. 40 %) in charged amino acids [6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Membrane-binding properties of phospholipase C-β1 and phospholipaseC-β2: role of the C-terminus and effects of polyphosphoinositides, G-proteins and Ca2+

Jenco

Becker

Morris

1997

Biochemical Journal

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We have studied the binding of two G-protein-regulated phospholipase C (PLC) enzymes, PLCs-beta1 and -beta2, to membrane surfaces using sucrose-loaded bilayer phospholipid vesicles of varying compositions. Neither enzyme binds appreciably to pure phosphatidylcholine vesicles at lipid concentrations up to 10(-3) M. PLC-beta1 and PLC-beta2 bind vesicles composed of phosphatidylcholine, phosphatidylserine and phosphatidylethanolamine (molar ratio 1:1:1) with an approximate Kd of 10(-5) M. Inclusion of 2% PtdIns(4,5)P2 in these vesicles had no effect on the affinity of this interaction. As reported by others, removal of the C-terminus of PLC-beta1 and PLC-beta2 produces catalytically active fragments. The affinity of these truncated proteins for phospholipid vesicles is dramatically reduced suggesting that this region of the proteins contains residues important for membrane binding. Inclusion of G-protein alpha- and betagamma-subunit activators in the phospholipid vesicles does not increase the binding of PLC-beta1 or PLC-beta2, and the magnitude of G-protein-mediated PLC activation observed at low phospholipid concentrations (10(-6) M) is comparable to that observed at concentrations at which the enzymes are predominantly membrane-bound (10(-3) M). PLC-beta1 and -beta2 contain C2 domains but Ca2+ does not enhance binding to the vesicles. Our results indicate that binding of these enzymes to membranes involves the C-temini of the proteins and suggest that activation of these enzymes by G-proteins results from a regulated interaction between the membrane-bound proteins rather than G-protein-dependent recruitment of soluble enzymes to a substrate-containing phospholipid surface.

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Section: Introductionmentioning

confidence: 99%

Membrane-binding properties of phospholipase C-β1 and phospholipaseC-β2: role of the C-terminus and effects of polyphosphoinositides, G-proteins and Ca2+

Jenco

Becker

Morris

1997

Biochemical Journal

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“…This InsP $ -Ca# + cross-coupling (ICC) scheme is supported by several lines of evidence. Firstly, the activity of PLC can be regulated by Ca# + [13][14][15], and Ca# + -stimulated inositol phosphate production has been demonstrated in several cell types following permeabilization [16][17][18]. Second, experimental manipulations which alter the amplitude of hormone-mediated Ca# + signals in intact cells can affect inositol phosphate production in some cell types [17,[19][20][21], although not in all [22].…”

Section: Introductionmentioning

confidence: 99%

Extracellular calcium concentration controls the frequency of intracellular calcium spiking independently of inositol 1,4,5-trisphosphate production in HeLa cells

Bootman

Young

et al. 1996

Biochemical Journal

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Stimulation of single HeLa cells with histamine evoked repetitive increases of the intracellular calcium ion concentration (Ca2+ spikes). The frequency of Ca2+ spiking increased as the extracellular hormone concentration was elevated. In addition, the frequency of Ca2+ spiking could be accelerated by increasing the extracellular Ca2+ concentration ([Ca2+]0) in the presence of a constant hormone concentration. The range of [Ca2+]0 over which the spiking frequency could be titrated was nominally-zero to 10mM, being half-maximally effective at approx. 1 and 2.5mM for 37 and 22 degrees C respectively. The effect of [Ca2+]0 on inositol phosphates production was also examined. Changes of [Ca2+]0 over a range which had been found to affect the frequency of Ca2+ spiking did not have any effect on the rate of myo-inositol 1,4,5-trisphosphate (InsP3) production, although an increase in inositol phosphates production was observed as [Ca2+]0 was increased from zero to values giving less than half-maximal Ca2+ spike frequency. These data suggest that at low Ca2+ spike frequency, Ca2+-stimulated activation of phospholipase C may contribute to Ca2+ spiking in HeLa cells, but under some conditions the availability of Ca2+ to the intracellular stores, rather than changes in the rate of InsP3 production, determines the Ca2+ spike frequency.

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“…PLC ␤ is activated by G proteins, while PLC ␥ is activated by tyrosine kinases. The regulation of PLC ␦ is poorly understood, although the enzymatic activ-ity of all 3 PLC isoforms can be stimulated by an increase in Ca 2 ϩ (Park et al, 1992;Wahl et al, 1992;Banno et al, 1994). Very likely the generation of IP 3 at fertilization results from the activation of one of these isoforms of phospholipase C.…”

mentioning

confidence: 99%

Calcium Release at Fertilization in Starfish Eggs Is Mediated by Phospholipase Cγ

Carroll

Ramarao

Mehlmann

et al. 1997

The Journal of Cell Biology

136

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Although inositol trisphosphate (IP3) functions in releasing Ca2+ in eggs at fertilization, it is not known how fertilization activates the phospholipase C that produces IP3. To distinguish between a role for PLCγ, which is activated when its two src homology-2 (SH2) domains bind to an activated tyrosine kinase, and PLCβ, which is activated by a G protein, we injected starfish eggs with a PLCγ SH2 domain fusion protein that inhibits activation of PLCγ. In these eggs, Ca2+ release at fertilization was delayed, or with a high concentration of protein and a low concentration of sperm, completely inhibited. The PLCγSH2 protein is a specific inhibitor of PLCγ in the egg, since it did not inhibit PLCβ activation of Ca2+ release initiated by the serotonin 2c receptor, or activation of Ca2+ release by IP3 injection. Furthermore, injection of a PLCγ SH2 domain protein mutated at its phosphotyrosine binding site, or the SH2 domains of another protein (the phosphatase SHP2), did not inhibit Ca2+ release at fertilization. These results indicate that during fertilization of starfish eggs, activation of phospholipase Cγ by an SH2 domain-mediated process stimulates the production of IP3 that causes intracellular Ca2+ release.

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Cloning, sequencing, expression, and Gq-independent activation of phospholipase C-beta 2.

Cited by 167 publications

References 46 publications

Membrane-binding properties of phospholipase C-β1 and phospholipaseC-β2: role of the C-terminus and effects of polyphosphoinositides, G-proteins and Ca2+

Membrane-binding properties of phospholipase C-β1 and phospholipaseC-β2: role of the C-terminus and effects of polyphosphoinositides, G-proteins and Ca2+

Extracellular calcium concentration controls the frequency of intracellular calcium spiking independently of inositol 1,4,5-trisphosphate production in HeLa cells

Calcium Release at Fertilization in Starfish Eggs Is Mediated by Phospholipase Cγ

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