A 100 amino acid region in the GABA rho 1 subunit confers robust homo-oligomeric expression.
Retinal gamma-aminobutyric acid type C (GABAC) receptors are believed to be composed of rho subunits. Although rho 1 and rho 2 are over 80% similar, the whole-cell currents generated by rho 1 receptors in Xenopus oocytes are significantly greater than those generated by rho 2 receptors. In this study, chimeric subunits containing different portions of human rho 1 and human rho 2 were created to localize sequences facilitating robust rho 1 expression. Our results indicate that these sequences reside in a 100 amino acid domain in the N-terminus of rho 1, and may involve N-linked glycosylation. Since the N-terminus also contains subunit assembly signals, rho 1 receptors may be formed more efficiently than rho 2 receptors. Therefore, this study furthers our understanding of the molecular basis of GABA-mediated inhibition in the retina.
Hackam
A S
AS
Center for Medical Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
Wang
T L
TL
Guggino
W B
WB
Cutting
G R
GR
D000595:Amino Acid Sequence; D000818:Animals; D001704:Biopolymers; D006031:Glycosylation; D006801:Humans; D008969:Molecular Sequence Data; D018408:Patch-Clamp Techniques; D010446:Peptide Fragments / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D018079:Receptors, GABA / Q000737:chemistry*; D011993:Recombinant Fusion Proteins / Q000737:chemistry*; D014981:Xenopus
D001704:Biopolymers; D010446:Peptide Fragments; D018079:Receptors, GABA; D011993:Recombinant Fusion Proteins