The Drosophila peptidoglycan-recognition protein LF interacts with peptidoglycan-recognition protein LC to downregulate the Imd pathway

作者：Ba**ous Nada; Coste Franck; Leone Philippe; Vincentelli Renaud; Royet Julien; Kellenberger Christine; Roussel Alain^*

来源：EMBO Reports, 2011, 12(4): 327-333.

DOI：10.1038/embor.2011.19

• Drosophila
• innate immunity
• structural biology

The peptidoglycan (PGN)-recognition protein LF (PGRP-LF) is a specific negative regulator of the immune deficiency (Imd) pathway in Drosophila. We determine the crystal structure of the two PGRP domains constituting the ectodomain of PGRP-LF at 1.72 and 1.94 angstrom resolution. The structures show that the LFz and LFw domains do not have a PGN-docking groove that is found in other PGRP domains, and they cannot directly interact with PGN, as confirmed by biochemical-binding assays. By using surface plasmon resonance analysis, we show that the PGRP-LF ectodomain interacts with the PGRP-LCx ectodomain in the absence and presence of tracheal cytotoxin. Our results suggest a mechanism for downregulation of the Imd pathway on the basis of the competition between PRGP-LCa and PGRP-LF to bind to PGRP-LCx.

• 出版日期2011-4