Abstract: The present invention provides modified G protein &agr;-subunits which are characterized by constitutive localization to the plasma membrane; enhanced binding to one or more of the normal receptor binding partners for that &agr;-subunit; and efficient binding to and activation of G protein binding partners. The distribution of these modified &agr;-subunits, which are “tethered” to the plasma membrane, allows the regulation of receptor-G protein coupling, and thus G-protein signaling, in various biological systems.

Abstract: The present invention features a human Nkx-6.1 polypeptide and nucleotide sequences encoding Nkx-6.1 polypeptides. In a particular aspect, the polynucleotide is the nucleotide sequence of SEQ ID NO:1. In addition, the invention features polynucleotide sequences that hybridize under stringent conditions to SEQ ID NO:1. In related aspects the invention features expression vectors and host cells comprising polynucleotides that encode a human Nkx-6.1 polypeptide. The present invention also relates to antibodies that bind specifically to a human Nkx-6.1 polypeptide, and methods for producing human Nkx-6.1 polypeptides.