Abstract: Transmembrane receptors in the signaling pathways of bacterial chemotaxis systems influence cell motility by forming noncovalent complexes with the cytoplasmic signaling proteins to regulate their activity. The requirements for receptor-mediated activation of CheA, the principal kinase of the Escherichia coli chemotaxis signaling pathway, can be demonstrated using self-assembled clusters of a receptor fragment (CF) derived from the cytoplasmic domain of the aspartate receptor, Tar. Histidine-tagged Tar CF can be assembled on the surface of unilamellar vesicles via a lipid containing the Nickel-nitrilotriacetic acid moiety as a headgroup. The stability of such a complex can be controlled by the properties of the template including the size and composition, which can be used, for example, to vary the 2-dimensional concentration of receptor fragments. Surface-assembled CF is also found to serve as a substrate for receptor methylation, which is catalyzed by the receptor transferase.