Putative receptor for the plant growth hormone auxin identified and characterized by anti-idiotypic antibodies

The molecular mechanism of action of auxins, which are an important class of plant growth regulators, is not known. While they are thought to influence cellular processes such as gene expression and membrane hyperpolarization by binding to specific receptors, no receptor mediating these processes has been unambiguously identified. We describe the identification of a putative auxin receptor by using anti-idiotypic antibodies. We have demonstrated that a 65-kilodalton protein found in a wide range of plants specifically binds auxins. Furthermore, since it is localized to the nucleus, it is a candidate for an auxin receptor that mediates some nuclear process.