Structure-function correlation of chemokine receptor CXCR4
10.3321/j.issn:1000-5404.2001.02.022
- VernacularTitle:趋化因子受体CXCR4的结构与功能
- Author:
Hong ZHENG
1
;
Peiper C STEPHEN
;
Xi-Hua ZHU
Author Information
1. Third Military Medical University
- From:Journal of Third Military Medical University
2001;23(2):185-189
- CountryChina
- Language:Chinese
-
Abstract:
Objective To explore the correlation between structure domains and function of chemokine receptor CXCR4. Methods After the establishment of wild type chemokine receptor CXCR4 and CXCR2, 5 CXCR4/CXCR2 chimeras, 2 CXCR4 mutants stably expressed on CHO cell line, all variants' bound activity with the ligant recombinant human SDF-1β，signal transduction ability after stimulation and their function as coreceptor for HIV-1 were studied with ligand-binding assay, cytosensor/microphysiometry and cell-cell receptor gene fusion assay. Results Among all 7 changed CXCR4 receptors, 3 chimeras (2444a, 4442, 4222) and 1 mutant (CXCR4-Tr) could be bound with SDF-1β in various degrees, of which only 2444a totally and CXCR4-Tr partially maintained signaling. All changed receptors but 4222 could act as coreceptors for HIV-1 (LA1) in varying degrees. Conclusion Several structure domains of CXCR4 are involved in the binding with SDF-1β. Among these domains, N-terminal extracellular domain has high affinity bound capability with SDF-1β, and the 3rd extracellular loop contributes to the binding too. Although the C-terminal intracellular domain has no association with the maintenance of the overall structure of the receptor and the ligand bound capability, the signaling is decreased when this domain is truncated. For CXCR4 signaling, not only the conserved motif DRY box is needed, but also the characterized conformation of the whole molecule must be formed when activation is required. There are some overlaps between SDF-1β bound domains and coreceptor funtion domain in molecular structure of CXCR4.
