alpha1-Adrenergic receptors (ARs) play important roles in control of blood pressure, nasal congestion, muscle growth, and other processes. Two native subtypes (alpha1A and alpha1B) can be distinguished pharmacologically, and three subtypes have been cloned (alpha1B, alpha1C, and alpha1D). Although one of the cloned subtypes (alpha1D) was originally thought to encode the pharmacologically defined alpha1A subtype, recent data suggests that this is unlikely. The relationship between the cloned receptors and the native subtypes must be understood, and any additional cDNA clones obtained, before the biochemical and functional roles of alpha1-AR subtypes can be clearly understood. Human SKNMC neuroepithelioma cells express at least two alpha1-ARs, resembling the alpha1A, and alpha1B subtypes. We have isolated, expressed, and partially characterized a full length chimeric genomic/cDNA clone from this cell line which is homologous to the rat alpha1D. We will use sense expression and antisense knockout of this and other human clones in SKNMC cells to clarify the relationship of the known clones to the pharmacological alpha1A subtype. If they are unrelated, as expected, we will obtain a full length alpha1A cDNA by expression cloning. With these clones we will be able to clearly define the drug specificities, signalling mechanisms, and interactions of alpha1-AR subtypes. Our major goals include: 1. To clearly define the relationship between the 3 known clones and the pharmacologically defined alpha1A subtype; 2. To obtain a full-length cDNA for the alpha1A subtype by expression cloning; 3. To determine whether different alpha1-AR receptor subtypes preferentially couple to different second messenger systems; and 4. To determine whether different subtypes co-existing in the same cell have additive, synergistic or redundant interactions which may contribute to the confusion about the number and properties of alpha1-AR subtypes. These experiments will clarify the number, signalling mechanisms, and interactions of alpha1-AR subtypes. Since drugs acting on these receptors have considerable therapeutic importance, such information may have direct clinical impact.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
1R01NS032706-01A1
Application #
2271071
Study Section
Neurological Sciences Subcommittee 1 (NLS)
Project Start
1994-12-01
Project End
1998-11-30
Budget Start
1994-12-01
Budget End
1995-11-30
Support Year
1
Fiscal Year
1995
Total Cost
Indirect Cost
Name
Emory University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
042250712
City
Atlanta
State
GA
Country
United States
Zip Code
30322
Minneman, Kenneth P (2007) Heterodimerization and surface localization of G protein coupled receptors. Biochem Pharmacol 73:1043-50
Zhong, H; Murphy, T J; Minneman, K P (2000) Activation of signal transducers and activators of transcription by alpha(1A)-adrenergic receptor stimulation in PC12 cells. Mol Pharmacol 57:961-7
Zhong, H; Minneman, K P (2000) Use and pharmacological analysis of established and transfected cell lines expressing adrenergic receptors. Methods Mol Biol 126:221-34
Zhong, H; Minneman, K P (1999) Differential activation of mitogen-activated protein kinase pathways in PC12 cells by closely related alpha1-adrenergic receptor subtypes. J Neurochem 72:2388-96
Berts, A; Zhong, H; Minneman, K P (1999) No role for Ca++ or protein kinase C in alpha-1A adrenergic receptor activation of mitogen-activated protein kinase pathways in transfected PC12 cells. Mol Pharmacol 55:296-303
Williams, N G; Zhong, H; Minneman, K P (1998) Differential coupling of alpha1-, alpha2-, and beta-adrenergic receptors to mitogen-activated protein kinase pathways and differentiation in transfected PC12 cells. J Biol Chem 273:24624-32
Boss, V; Wang, X; Koppelman, L F et al. (1998) Histamine induces nuclear factor of activated T cell-mediated transcription and cyclosporin A-sensitive interleukin-8 mRNA expression in human umbilical vein endothelial cells. Mol Pharmacol 54:264-72
Wang, X; Murphy, T J (1998) Inhibition of cyclic AMP-dependent kinase by expression of a protein kinase inhibitor/enhanced green fluorescent fusion protein attenuates angiotensin II-induced type 1 AT1 receptor mRNA down-regulation in vascular smooth muscle cells. Mol Pharmacol 54:514-24
Theroux, T L; Esbenshade, T A; Peavy, R D et al. (1996) Coupling efficiencies of human alpha 1-adrenergic receptor subtypes: titration of receptor density and responsiveness with inducible and repressible expression vectors. Mol Pharmacol 50:1376-87
Zhong, H; Guerrero, S W; Esbenshade, T A et al. (1996) Inducible expression of beta 1- and beta 2-adrenergic receptors in rat C6 glioma cells: functional interactions between closely related subtypes. Mol Pharmacol 50:175-84