Intrasubunit signal transduction by the aspartate chemoreceptor.
Receptors that transmit signals across cell membranes are typically composed of multiple subunits. To test whether subunit interactions are required for transmembrane signaling by the bacterial aspartate receptor, dimers were constructed with (i) two full-length subunits, (ii) one full-length subunit and one subunit lacking the cytoplasmic domain, or (iii) one full-length subunit and one subunit lacking both the cytoplasmic and the transmembrane domains. Methylation of the cytoplasmic domain of all three receptor constructs was stimulated by the binding of aspartate. These findings demonstrate that transmembrane signaling does not require interactions between cytoplasmic or transmembrane domains of adjacent subunits and suggest that signaling occurs via conformational changes transduced through a single subunit.
Milligan
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Department of Molecular and Cell Biology, University of California, Berkeley 94720.
Koshland
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DE
D001224:Aspartic Acid / Q000502:physiology*; D004252:DNA Mutational Analysis; D008024:Ligands; D046911:Macromolecular Substances; D008745:Methylation; D011487:Protein Conformation; D017459:Receptors, Amino Acid; D011956:Receptors, Cell Surface / Q000737:chemistry*; D011994:Recombinant Proteins; D012486:Salmonella typhimurium; D015398:Signal Transduction; D013329:Structure-Activity Relationship
D008024:Ligands; D046911:Macromolecular Substances; D017459:Receptors, Amino Acid; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; C031959:aspartic acid receptor; D001224:Aspartic Acid