摘要：SummaryIt was posited that functionalities of GPCRs require full-length sequences that are negated by residue deletions. Here we report that significantly truncated nfCCR5QTYand nfCXCR4QTYstill bind native ligands. Receptor-ligand interactions were discovered from yeast 2-hybrid screening and confirmed by mating selection. Two nfCCR5QTY(SZ218a, SZ190b) and two nfCXCR4QTY(SZ158a, SZ146a) were expressed inE. coli. Synthesized receptors exhibited α-helical structures and bound respective ligands with reduced affinities. SZ190b and SZ158a were reconverted into non-QTY forms and expressed in HEK293T cells. Reconverted receptors localized on cell membranes and functioned as negative regulators for ligand-induced signaling when co-expressed with full-length receptors. CCR5-SZ190b individually can perform signaling at a reduced level with higher ligand concentration. Our findings provide insight into essential structural components for CCR5 and CXCR4 functionality, while raising the possibility that non-full-length receptors may be resulted from alternative splicing and that pseudo-genes in genomes may be present and functional in living organisms.Graphical AbstractDisplay OmittedHighlights•Y2H screening reveals ligand interaction from truncated CXCR4 and CCR5 in QTY form•Truncated CCR5QTYand CXCR4QTYcan be produced in E. coli and bind native ligands•Reconverted receptors localize on membranes and regulate cell signaling in HEK293•Our finding indicates potential presence and function for truncated receptorsMolecular Biology; Cell Biology; Structural Biology
