Identification of amino acid residues within GABA(A) receptor beta subunits that mediate both homomeric and heteromeric receptor expression

Pamela M. Taylor, Philip Thomas, George H. Gorrie, Christopher N. Connolly, Trevor G. Smart, Stephen J. Moss

    Research output: Contribution to journalArticle

    91 Citations (Scopus)

    Abstract

    GABA(A) receptors are believed to be heteropentamers that can be constructed from six subunit classes: alpha(1-6), beta(1-4), gamma(1-3), delta, epsilon, and pi. Given that individual neurons often express multiple receptor subunits, it is important to understand how these receptors assemble. To determine which domains of receptor subunits control assembly we have exploited the differing capabilities of the beta 2 and beta 3 subunits to form functional cell surface homomeric receptors. Using a chimeric approach, we have identified four amino acids in the N-terminal domain of the beta 3 subtlnit that mediate functional cell surface expression of this subunit compared with beta 2, which is retained within the endoplasmic reticulum. Substitution of these four amino acids-glycine 171, lysine 173, glutamate 179, and arginine 180-into the beta 2 subunit was sufficient to enable the beta 2 subunit to homo-oligomerize. The effect of this putative "assembly signal" on the production of heteromeric receptors composed of crp and pr subunits was also analyzed. This signal was not critical for the formation of receptors composed of either alpha 1 beta 2 or alpha 1 beta 3 subunits, suggesting that mutation of these residues did not disrupt subunit folding. However, this signal was important in the formation of beta gamma 2 receptors. These residues did not seem to affect the initial association of beta 2 and gamma 2 subunits but appeared to be important for the subsequent production of functional receptors. Our studies identify, for the first time, key residues within the N-terminal domains of receptor beta subunits that mediate the selective assembly of GABA(A) receptors.

    Original languageEnglish
    Pages (from-to)6360-6371
    Number of pages12
    JournalJournal of Neuroscience
    Volume19
    Issue number15
    Publication statusPublished - 1 Aug 1999

    Keywords

    • GABA receptor
    • Homomeric
    • Heteromeric
    • Assembly
    • Benzodiazepine
    • Cell surface

    Cite this

    Taylor, Pamela M. ; Thomas, Philip ; Gorrie, George H. ; Connolly, Christopher N. ; Smart, Trevor G. ; Moss, Stephen J. / Identification of amino acid residues within GABA(A) receptor beta subunits that mediate both homomeric and heteromeric receptor expression. In: Journal of Neuroscience. 1999 ; Vol. 19, No. 15. pp. 6360-6371.
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    Identification of amino acid residues within GABA(A) receptor beta subunits that mediate both homomeric and heteromeric receptor expression. / Taylor, Pamela M.; Thomas, Philip; Gorrie, George H.; Connolly, Christopher N. ; Smart, Trevor G.; Moss, Stephen J.

    In: Journal of Neuroscience, Vol. 19, No. 15, 01.08.1999, p. 6360-6371.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Identification of amino acid residues within GABA(A) receptor beta subunits that mediate both homomeric and heteromeric receptor expression

    AU - Taylor, Pamela M.

    AU - Thomas, Philip

    AU - Gorrie, George H.

    AU - Connolly, Christopher N.

    AU - Smart, Trevor G.

    AU - Moss, Stephen J.

    PY - 1999/8/1

    Y1 - 1999/8/1

    N2 - GABA(A) receptors are believed to be heteropentamers that can be constructed from six subunit classes: alpha(1-6), beta(1-4), gamma(1-3), delta, epsilon, and pi. Given that individual neurons often express multiple receptor subunits, it is important to understand how these receptors assemble. To determine which domains of receptor subunits control assembly we have exploited the differing capabilities of the beta 2 and beta 3 subunits to form functional cell surface homomeric receptors. Using a chimeric approach, we have identified four amino acids in the N-terminal domain of the beta 3 subtlnit that mediate functional cell surface expression of this subunit compared with beta 2, which is retained within the endoplasmic reticulum. Substitution of these four amino acids-glycine 171, lysine 173, glutamate 179, and arginine 180-into the beta 2 subunit was sufficient to enable the beta 2 subunit to homo-oligomerize. The effect of this putative "assembly signal" on the production of heteromeric receptors composed of crp and pr subunits was also analyzed. This signal was not critical for the formation of receptors composed of either alpha 1 beta 2 or alpha 1 beta 3 subunits, suggesting that mutation of these residues did not disrupt subunit folding. However, this signal was important in the formation of beta gamma 2 receptors. These residues did not seem to affect the initial association of beta 2 and gamma 2 subunits but appeared to be important for the subsequent production of functional receptors. Our studies identify, for the first time, key residues within the N-terminal domains of receptor beta subunits that mediate the selective assembly of GABA(A) receptors.

    AB - GABA(A) receptors are believed to be heteropentamers that can be constructed from six subunit classes: alpha(1-6), beta(1-4), gamma(1-3), delta, epsilon, and pi. Given that individual neurons often express multiple receptor subunits, it is important to understand how these receptors assemble. To determine which domains of receptor subunits control assembly we have exploited the differing capabilities of the beta 2 and beta 3 subunits to form functional cell surface homomeric receptors. Using a chimeric approach, we have identified four amino acids in the N-terminal domain of the beta 3 subtlnit that mediate functional cell surface expression of this subunit compared with beta 2, which is retained within the endoplasmic reticulum. Substitution of these four amino acids-glycine 171, lysine 173, glutamate 179, and arginine 180-into the beta 2 subunit was sufficient to enable the beta 2 subunit to homo-oligomerize. The effect of this putative "assembly signal" on the production of heteromeric receptors composed of crp and pr subunits was also analyzed. This signal was not critical for the formation of receptors composed of either alpha 1 beta 2 or alpha 1 beta 3 subunits, suggesting that mutation of these residues did not disrupt subunit folding. However, this signal was important in the formation of beta gamma 2 receptors. These residues did not seem to affect the initial association of beta 2 and gamma 2 subunits but appeared to be important for the subsequent production of functional receptors. Our studies identify, for the first time, key residues within the N-terminal domains of receptor beta subunits that mediate the selective assembly of GABA(A) receptors.

    KW - GABA receptor

    KW - Homomeric

    KW - Heteromeric

    KW - Assembly

    KW - Benzodiazepine

    KW - Cell surface

    M3 - Article

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    SP - 6360

    EP - 6371

    JO - Journal of Neuroscience

    JF - Journal of Neuroscience

    SN - 0270-6474

    IS - 15

    ER -