Characteristics of P2X7 receptors from human B lymphocytes expressed in Xenopus oocytes

Klapperstück, Manuela; Büttner, Cora; Böhm, Thomas; Schmalzing, Günther; Markwardt, Fritz

doi:10.1016/s0005-2736(00)00245-5

Cited by 62 publications

(77 citation statements)

References 33 publications

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“…3A, lower right). Apart from the slowly increasing conductance following washout of the agonist, this current behavior matches rather closely the behavior of human P2X 7 receptor expressed in oocytes [14,18]. In contrast, the rat subtype, when expressed in oocytes, undergoes a strong current run-down following activation [13].…”

Section: Functional Expression Of Xp2x 7 In Xenopus Oocytessupporting

confidence: 62%

The P2X₇ receptor from Xenopus laevis: formation of a large pore in Xenopus oocytes

2002

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The purinergic P2X 7 receptor is an ATP-receptor channel predominantly expressed in immune cells. P2X 7 has been cloned from human, rat and mouse. Here we report cloning of the Xenopus laevis P2X 7 receptor (xP2X 7 ). xP2X 7 is only about 50% identical to the mammalian homologues, shows a broad tissue expression pattern, and has the electrophysiological characteristics typical of a P2X 7 receptor: low agonist affinity (EC 50 about 2.6 mM) and a non-desensitizing current. Moreover, expression of xP2X 7 in Xenopus oocytes is sufficient to induce the formation of a large pore, which is permeable to large cations such as NMDG + . Identification of a nonmammalian P2X 7 receptor may help to identify functionally important parts of the protein. ß

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Section: Functional Expression Of Xp2x 7 In Xenopus Oocytessupporting

confidence: 62%

The P2X₇ receptor from Xenopus laevis: formation of a large pore in Xenopus oocytes

2002

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“…So, for example, only slightly permeant pores, or none at all develop in human fibroblasts, osteoblasts and Mueller cells in response to ligand binding to P2X 7 R (Solini et al, 1999;Nakamura et al, 2000;Pannicke et al, 2000). Cloned P2X 7 R's form large pores in HEK cells (Surprenant et al, 1996;Virginio et al, 1999a), but none at all in Xenopus oocytes (Klapperstuck et al, 2000). Human B cells also possess pores of limited permeability that take up YO-PRO-1, but not PI (Markwardt et al, 1997;Gu et al, 2000;Lohn et al, 2001).…”

Section: Discussionmentioning

confidence: 99%

The cytokine IL‐1β transiently enhances P2X₇ receptor expression and function in human astrocytes

Narcisse

Scemes

Zhao

et al. 2004

Glia

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147

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Extracellular nucleotide di-and triphosphates such as ATP and ADP mediate their effects through purinergic P2 receptors belonging to either the metabotropic P2Y or the ionotropic P2X receptor family. The P2X 7 R is a unique member of the P2X family, which forms a pore in response to ligand stimulation, regulating cell permeability, cytokine release, and/or apoptosis. This receptor is also unique in that its affinity for the ligand benzoyl-benzoyl ATP (BzATP) is at least 10-fold greater than that of ATP. Primary human fetal astrocytes in culture express low-levels of P2X 7 R mRNA and protein, and BzATP induces only a slight influx in intracellular calcium [Ca 2+ ] i , with little demonstrable effect on gene expression or pore formation in these cells. We now show that, following treatment with the proinflammatory cytokine IL-1β, BzATP induces a robust rise in [Ca 2+ ] i with agonist and antagonist profiles indicative of the P2X 7 R. IL-1β also induced the formation of membrane pores as evidenced by the uptake of YO-PRO-1 (375 Da). Quantitative real-time PCR demonstrated transient upregulation of P2X 7 R mRNA in IL-1β-treated cells, while FACS analysis indicated a similar upregulation of P2X 7 R protein at the cell membrane. In multiple sclerosis lesions, immunoreactivity for the P2X 7 R was demonstrated on reactive astrocytes in autopsy brain tissues. In turn, P2X 7 R stimulation increased the production of IL-1-induced nitric oxide synthase activity by astrocytes in culture. These studies suggest that signaling via the P2X 7 R may modulate the astrocytic response to inflammation in the human central nervous system.

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“…In the Xenopus oocyte expression system, the onset and offset kinetics of ATP at the human P2X 7 receptor show two components (248,250). This suggests that under these conditions (divalent-free solutions) ATP binds to at least two sites that differ in affinity by ϳ50-fold.…”

Section: Agonistsmentioning

confidence: 99%

Molecular Physiology of P2X Receptors

North

2002

Physiological Reviews

2,673

128

3,397

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P2X receptors are membrane ion channels that open in response to the binding of extracellular ATP. Seven genes in vertebrates encode P2X receptor subunits, which are 40–50% identical in amino acid sequence. Each subunit has two transmembrane domains, separated by an extracellular domain (∼280 amino acids). Channels form as multimers of several subunits. Homomeric P2X1, P2X2, P2X3, P2X4, P2X5, and P2X7 channels and heteromeric P2X2/3 and P2X1/5 channels have been most fully characterized following heterologous expression. Some agonists (e.g., αβ-methylene ATP) and antagonists [e.g., 2′,3′- O-(2,4,6-trinitrophenyl)-ATP] are strongly selective for receptors containing P2X1 and P2X3subunits. All P2X receptors are permeable to small monovalent cations; some have significant calcium or anion permeability. In many cells, activation of homomeric P2X7 receptors induces a permeability increase to larger organic cations including some fluorescent dyes and also signals to the cytoskeleton; these changes probably involve additional interacting proteins. P2X receptors are abundantly distributed, and functional responses are seen in neurons, glia, epithelia, endothelia, bone, muscle, and hemopoietic tissues. The molecular composition of native receptors is becoming understood, and some cells express more than one type of P2X receptor. On smooth muscles, P2X receptors respond to ATP released from sympathetic motor nerves (e.g., in ejaculation). On sensory nerves, they are involved in the initiation of afferent signals in several viscera (e.g., bladder, intestine) and play a key role in sensing tissue-damaging and inflammatory stimuli. Paracrine roles for ATP signaling through P2X receptors are likely in neurohypophysis, ducted glands, airway epithelia, kidney, bone, and hemopoietic tissues. In the last case, P2X7 receptor activation stimulates cytokine release by engaging intracellular signaling pathways.

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Characteristics of P2X7 receptors from human B lymphocytes expressed in Xenopus oocytes

Cited by 62 publications

References 33 publications

The P2X₇ receptor from Xenopus laevis: formation of a large pore in Xenopus oocytes

The P2X₇ receptor from Xenopus laevis: formation of a large pore in Xenopus oocytes

The cytokine IL‐1β transiently enhances P2X₇ receptor expression and function in human astrocytes

Molecular Physiology of P2X Receptors

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Characteristics of P2X7 receptors from human B lymphocytes expressed in Xenopus oocytes

Cited by 62 publications

References 33 publications

The P2X7 receptor from Xenopus laevis: formation of a large pore in Xenopus oocytes

The P2X7 receptor from Xenopus laevis: formation of a large pore in Xenopus oocytes

The cytokine IL‐1β transiently enhances P2X7 receptor expression and function in human astrocytes

Molecular Physiology of P2X Receptors

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Product

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The P2X₇ receptor from Xenopus laevis: formation of a large pore in Xenopus oocytes

The P2X₇ receptor from Xenopus laevis: formation of a large pore in Xenopus oocytes

The cytokine IL‐1β transiently enhances P2X₇ receptor expression and function in human astrocytes