Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Recombinant dna technique included in method of making a...
Reexamination Certificate
1999-11-08
2003-03-18
Kunz, Gary L. (Department: 1647)
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Recombinant dna technique included in method of making a...
C435S069100, C435S366000, C435S320100, C435S325000, C536S023500, C536S023100, C530S350000
Reexamination Certificate
active
06534289
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to chimeric receptors containing one or more regions homologous to a metabotropic glutamate receptor and one or more regions homologous to a calcium receptor.
BACKGROUND OF THE INVENTION
The following description provides a summary of information relevant to the present invention. It is not an admission that any of the information provided herein is prior art to the presently claimed invention, nor that any of the publications specifically or implicitly referenced are prior art to that invention.
Glutamate is the major excitatory neurotransmitter in the mammalian brain. Glutamate produces its effects on central neurons by binding to and thereby activating cell surface receptors. These receptors have been subdivided into two major classes, the ionotropic and metabotropic glutamate receptors, based on the structural features of the receptor proteins, the means by which the receptors transduce signals into the cell, and pharmacological profiles.
The ionotropic glutamate receptors (iGluRs) are ligand-gated ion channels that, upon binding glutamate, open to allow the selective influx of certain monovalent and divalent cations, thereby depolarizing the cell membrane. In addition, certain iGluRs with relatively high calcium permeability can activate a variety of calcium-dependent intracellular processes. These receptors are multisubunit protein complexes that may be homomeric or heteromeric in nature. The various iGluR subunits all share common structural motifs, including a relatively large amino-terminal extracellular domain (ECD), followed by a multiple transmembrane domain (TMD) comprising two membrane-spanning regions (TMs), a second smaller intracellular loop, and a third TM, before terminating with an intracellular carboxy-terminal domain (CT). Historically the iGluRs were first subdivided pharmacologically into three classes based on preferential activation by the agonists alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA), kainate (KA), and N-methyl-D-aspartate (NMDA). Later, molecular cloning studies coupled with additional pharmacological studies revealed a greater diversity of iGluRs, in that multiple subtypes of AMPA, KA and NMDA receptors are expressed in the mammalian CNS (Hollman and Heinemann,
Ann. Rev. Neurosci.
7:31, 1994).
The metabotropic glutamate receptors (mGluRs) are G protein-coupled receptors capable of activating a variety of intracellular second messenger systems following the binding of glutamate or other potent agonists including quisqualate and 1-aminocyclopentane-1,3-dicarboxylic acid (trans-ACPD) (Schoepp et al.,
Trends Pharmacol. Sci.
11:508, 1990; Schoepp and Conn,
Trends Pharmacol. Sci.
14:13, 1993).
Activation of different metabotropic glutamate receptor subtypes in situ elicits one or more of the following responses: activation of phospholipase C, increases in phosphoinositide (PI) hydrolysis, intracellular calcium release, activation of phospholipase D, activation or inhibition of adenylyl cyclase, increases and decreases in the formation of cyclic adenosine monophosphate (cAMP), activation of guanylyl cyclase, increases in the formation of cyclic guanosine monophosphate (cGMP), activation of phospholipase A
2
, increases in arachidonic acid release, and increases or decreases in the activity of voltage- and ligand-gated ion channels (Schoepp and Conn,
Trends Pharmacol. Sci.
14:13, 1993; Schoepp,
Neurochem. Int.
24:439, 1994; Pin and Duvoisin,
Neuropharmacology
34:1, 1995).
Thus far, eight distinct mGluR subtypes have been isolated via molecular cloning, and named mGluR1 to mGluR8 according to the order in which they were discovered (Nakanishi,
Neuron
13:1031, 1994, Pin and Duvoisin,
Neuropharmacology
34:1, 1995; Knopfel et al.,
J. Med. Chem.
38:1417, 1995). Further diversity occurs through the expression of alternatively spliced forms of certain mGluR subtypes (Pin et al.,
PNAS
89:10331, 1992; Minakami et al.,
BBRC
199:1136, 1994). All of the mGluRs are structurally similar, in that they are single subunit membrane proteins possessing a large amino-terminal extracellular domain (ECD) followed by seven putative transmembrane domain (7TMD) comprising seven putative membrane spanning helices connected by three intracellular and three extracellular loops, and an intracellular carboxy-terminal domain of variable length (cytoplasmic tail) (CT) (see, Schematic
FIG. 1
a
).
The eight mGluRs have been subdivided into three groups based on amino acid sequence identities, the second messenger systems they utilize, and pharmacological characteristics (Nakanishi,
Neuron
13:1031, 1994; Pine and Duvoisin,
Neuropharmacology
34:1, 1995; Knopfel et al.,
J. Med. Chem.
38:1417, 1995). The amino acid identity between mGluRs within a given group is approximately 70% but drops to about 40% between mGluRs in different groups. For mGluRs in the same group, this relatedness is roughly paralleled by similarities in signal transduction mechanisms and pharmacological characteristics.
The Group I mGluRs comprise mGluR1, mGluR5and their alternatively spliced variants. The binding of agonists to these receptors results in the activation of phospholipase C and the subsequent mobilization of intracellular calcium. For example, Xenopus oocytes expressing recombinant mGluR1 receptors have been utilized to demonstrate this effect indirectly by electrophysiological means (Masu et al.,
Nature
349:760, 1991; Pin et al.,
PNAS
89:10331, 1992). Similar results were achieved with oocytes expressing recombinant mGluR5 receptors (Abe et al.,
J. Biol. Chem.
267:13361, 1992; Minakami et al.,
BBRC
199:1136, 1994). Alternatively, agonist activation of recombinant mGluR1 receptors expressed in Chinese hamster ovary (CHO) cells stimulated PI hydrolysis, cAMP formation, and arachidonic acid release as measured by standard biochemical assays (Aramori and Nakanishi,
Neuron
8:757, 1992). In comparison, activation of mGluR5 receptors expressed in CHO cells stimulated PI hydrolysis and subsequent intracellular calcium transients but no stimulation of cAMP formation or arachidonic acid release was observed (Abe et al.,
J. Biol. Chem.
267:13361, 1992). The agonist potency profile for Group I mGluRs is quisqualate>glutamate=ibotenate>(2S,1′S,2′S)-2-carboxycyclopropyl)glycine (L-CCG-I)>(1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (ACPD). Quisqualate is relatively selective for Group I receptors, as compared to Group II and Group III mGluRs, but it also potently activates ionotropic AMPA receptors (Pin and Duvoisin, Neuropharmacology, 34:1, Knopfel et al.,
J. Med. Chem.
38:1417, 1995).
The Group II mGluRs include mGluR2 and mGluR3. Activation of these receptors as expressed in CHO cells inhibits adenylyl cyclase activity via the inhibitory G protein, G
i
, in a pertussis toxin-sensitive fashion (Tanabe et al.,
Neuron
8:169, 1992; Tanabe et al.,
Neurosci.
13:1372, 1993). The agonist potency profile for Group II receptors is L-CCG-I>glutamate>ACPD>ibotenate>quisqualate. Preliminary studies suggest that L-CCG-I and (2S,1′R,2′R,3′R)-2-(2,3-dicarboxycyclopropyl)glycine (DCG-IV) are both relatively selective agonists for the Group II receptors (Knopfel et al.,
J. Med. Chem.
38:1417, 1995).
The Group III mGluRs include mGluR4, mGluR6, mGluR7 and mGluR8. Like the Group II receptors these mGluRs are negatively coupled to adenylate cyclase to inhibit intracellular cAMP accumulation in a pertussis toxin-sensitive fashion when expressed in CHO cells (Tanabe et al.,
J. Neurosci.
13:1372, 1993; Nakajima et al.,
J. Biol. Chem.
268:11868, 1993; Okamoto et al.,
J. Biol. Chem.
269:1231, 1994; Duvoisin et al.,
J. Neurosci.
15:3075, 1995). As a group, their agonist potency profile is (S)-2-amino-4-phosphonobutyric acid (L-AP4)>glutamate>ACPD>quisqualate, but mGluR8 may differ slightly with glutamate being more potent than L-AP4 (Knopfel et al.,
J. Med. Chem.
38:1417, 1995; Duvoisin et al.,
J. Neurosci.
15:3075, 1995). Both L-AP4
Fuller Forrest H.
Hammerland Lance G.
Krapcho Karen J.
Storjohann Laura L.
Stormann Thomas M.
Kunz Gary L.
NPS Pharmaceuticals Inc.
Warburg Richard J.
Wegert Sandra
LandOfFree
Nucleic acids encoding mGLuR/CaR chimera does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Nucleic acids encoding mGLuR/CaR chimera, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nucleic acids encoding mGLuR/CaR chimera will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3024509