Disease relevance of PLCB4

• By using a retrovirus-derived system we generated derivatives of the human colon adenocarcinoma cell line LS174T (ATCC CL 188) that stably overexpress a full-length cDNA encoding the beta 1 isoform of bovine phosphoinositides-specific phospholipase C (PI-PLC) [1].
• After a prolonged reperfusion time of 7 days after ischemia, both cytosolic and membrane-bound forms of PI-PLC were activated [2].
• We conclude that the degradation of phosphatidylinositol by cytosolic phosphoinositide-phospholipase C may contribute to the pathophysiology of delayed neuronal death following cerebral ischemia [2].
• Ischemia-reperfusion injury had no effect on Abeta-evoked alterations of synaptic plasma membrane-bound PI-PLC [2].
• Phosphatidylinositol-specific phospholipase C (PIPLC) treatment of a B lymphoma cell line released 35% of the cell surface LFA-3 and 62% of DAF [3].

Psychiatry related information on PLCB4

• The release of the neuraminidase by PI-PLC was dependent on the reaction time and the concentration of PI-PLC [4].

High impact information on PLCB4

• Mammalian phosphoinositide-specific phospholipase C enzymes (PI-PLC) act as signal transducers that generate two second messengers, inositol-1,4,5-trisphosphate and diacylglycerol [5].
• The best characterized of the intranuclear lipids are the inositol lipids that form the components of a phosphoinositide-phospholipase C cycle [6].
• The protein on NK cells has a molecular mass 6-10 kD larger than that on PMN, and, unlike the latter, is resistant to PI-specific phospholipase C (PI-PLC) [7].
• However, when LFA-3 purified from human E was reconstituted in sheep E or human E and subjected to PIPLC treatment, 40-50% of LFA-3 was released from the cell membrane [3].
• Treatment with PI-specific phospholipase C (PIPLC) releases 70-80, 60, and 10% of cell surface DAF from mononuclear cells, neutrophils, and erythrocytes, respectively [8].

Chemical compound and disease context of PLCB4

• The X-ray crystal structure of the phosphatidylinositol-specific phospholipase C (PI-PLC) from the human pathogen Listeria monocytogenes has been determined both in free form at 2.0 A resolution, and in complex with the competitive inhibitor myo-inositol at 2.6 A resolution [9].
• Quantitative solubilization of the phospholipid-associated form of acetylcholinesterase (AChE) from Torpedo electric organ can be achieved in the absence of detergent by treatment with phosphatidylinositol-specific phospholipase C (PIPLC) from Staphylococcus aureus [Futerman, Low & Silman (1983) Neurosci. Lett. 40, 85-89] [10].
• A significant fraction of the amphiphilic AChE species was converted into hydrophilic components by incubation of the soluble enzyme with phosphatidylinositol-specific phospholipase C (PIPLC) from Bacillus thuringiensis, this fraction being increased by a double treatment with PIPLC and alkaline hydroxylamine [11].
• In digitonin-permeabilized C6 glioma cells, the concentration-dependent increase of PI-PLC activation elicited by free Ca2+ was potentiated by the GTP analogue, guanosine 5'-[gamma-thio]triphosphate (GTP gamma S), with an EC50 of 6 microM [12].
• This phosphonate inhibited the activity of phosphatidyl inositol-specific phospholipase C (PI-PLC) from Bacillus cereus with an IC50 of approximately 10 mM [13].

Biological context of PLCB4

• Transient transfection assays were used to determine how the activity of phospholipase C beta 4, which is preferentially expressed in retina, was regulated [14].
• OBJECTIVE: The enzyme phosphoinositide-specific phospholipase C (PI-PLC) is a component of the phosphoinositide signal transduction system [15].
• The results showed that suppression of PI-PLC promoted VEC apoptosis by inhibiting Akt phosphorylation, elevating P53 expression, and affecting the cell cycle distribution [16].
• In the authors' previous studies, they found that phosphatidylcholine-specific phospholipase C (PC-PLC) and phosphatidylinositol-specific phospholipase C (PI-PLC) played contrary roles in the apoptosis of vascular endothelial cells (VECs), but the mechanism underlying the phenomenon remains unclear [16].
• The cDNA encoding rat PLC-beta 4 has been cloned from a cDNA library prepared from rat brain [17].

Anatomical context of PLCB4

• The stimulation of T cell receptor by cross-linked anti-CD3 mAb resulted in a rapid increase of the phosphatidylinositol-specific phospholipase C (PI-PLC) activity in whole cell lysates [18].
• Tat, however, selectively stimulated a nuclear-specific PI-PLC with a peak of activity after 30 min from the addition in culture to Jurkat cells [18].
• PI-PLC beta 1 overexpresser clones grew to form cell clumps floating in liquid medium, whereas the pMV7-introduced control clones displayed morphologic characteristics that were very similar to those of the parent LS174T cell line [1].
• A combination of conventional and immunoaffinity chromatographic techniques was used to purify PIPLC beta 1 and beta 3 from rat brain membranes [19].
• PIPLC beta 2 was purified from cytosol of HL60 cells [19].

Associations of PLCB4 with chemical compounds

• cDNA sequence and gene locus of the human retinal phosphoinositide-specific phospholipase-C beta 4 (PLCB4) [20].
• Phosphatidyl inositol-phospholipase C (PI-PLC) in squid retina was studied by immunoblotting and its activities were determined using [3H]phosphatidyl inositol bisphosphate ([3H]PIP2) as substrate [21].
• GTP gamma S stimulated only the PI-PLC activity associated with membrane and was magnesium dependent [21].
• A neurotoxic fragment of amyloid, Abeta 25-35, incubated in the presence of endogenous Ca2+, increased significantly the PI-PLC activity of normoxic brain [2].
• These results provide evidence for a nonconserved role of this conserved alanine in coupling of group I GPCRs to PI PLC-activating G proteins and also suggest that this residue has differential roles in regulating expression and signaling by rat and human PAFRs [22].

Other interactions of PLCB4

• Compared with normal platelets, platelets from the patient contained approximately one-third the amount of PLC-beta 2, whereas PLC-beta 4 was increased threefold [23].
• These results indicate that phospholipase C beta 4 is activated by G alpha subunits that are members of the Gq class, and, like the phospholipase C beta 1 isoform, it is refractory to activation in the transfection assay by many of the combinations of beta and gamma subunits found in the heterotrimeric G-proteins [14].

Analytical, diagnostic and therapeutic context of PLCB4

• PI-PLC activity was determined by enzymatic assay, and protein expression of the PLC isozymes was determined by the Western blot technique [15].
• Protein sequence analysis of a bovine brain phosphoinositide-specific phospholipase C (PI-PLC; PLC-154) has permitted the isolation of a cDNA that appears to code for this protein [24].
• The availability of a highly specific probe moved us to perform in patients affected with MDS/AML, associated with normal karyotype, painting and fluorescence in situ hybridization (FISH) analysis aimed to check the inositide-specific phospholipase C (PI-PLC) beta1 gene, a player in the control of some checkpoints of the cell cycle [25].
• The effective resolution of human platelet cytosolic phosphoinositide-phospholipase C (PLC) revealed five distinct activity peaks by Q-Sepharose and heparin-Sepharose column chromatographies when assayed using phosphatidylinositol (PI) and phosphatidylinositol 4,5-bisphosphate (PIP2) [26].
• No role for glycosylphosphatidyl-inositol (GPI)-linked structures was demonstrated in these binding assays because the adhesion of leukemic blasts to stroma was not diminished after treatment with phosphatidylinositol-specific phospholipase C (PI-PLC) [27].

References