Structural Features of an Extended C-Terminal Tail Modulate the Function of the Chemokine CCL21

Natasha A. Moussouras, Gertrud M. Hjortø, Francis C. Peterson, Martyna Szpakowska, Andy Chevigné, Mette M. Rosenkilde, Brian F. Volkman*, Michael B. Dwinell

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

7 Citations (Scopus)

Abstract

The chemokines CCL21 and CCL19, through binding of their cognate receptor CCR7, orchestrate lymph node homing of dendritic cells and naïve T cells. CCL21 differs from CCL19 via an unstructured 32 residue C-terminal domain. Previously described roles for the CCL21 C-terminus include GAG-binding, spatial localization to lymphatic vessels, and autoinhibitory modulation of CCR7-mediated chemotaxis. While truncation of the C-terminal tail induced chemical shift changes in the folded chemokine domain, the structural basis for its influence on CCL21 function remains largely unexplored. CCL21 concentration-dependent NMR chemical shifts revealed weak, nonphysiological self-association that mimics the truncation of the C-terminal tail. We generated a series of C-terminal truncation variants to dissect the C-terminus influence on CCL21 structure and receptor activation. Using NMR spectroscopy, we found that CCL21 residues 80-90 mediate contacts with the chemokine domain. In cell-based assays for CCR7 and ACKR4 activation, we also found that residues 92-100 reduced CCL21 potency in calcium flux, cAMP inhibition, and β-arrestin recruitment. Taken together, these structure-function studies support a model wherein intramolecular interactions with specific residues of the flexible C-terminus stabilize a less active monomer conformation of the CCL21. We speculate that the autoinhibitory intramolecular contacts between the C-terminal tail and chemokine body are disrupted by GAG binding and/or interactions with the CCR7 receptor to ensure optimal functionality.

Original languageEnglish
Pages (from-to)1338-1350
Number of pages13
JournalBiochemistry
Volume59
Issue number13
DOIs
Publication statusPublished - 7 Apr 2020

Fingerprint

Dive into the research topics of 'Structural Features of an Extended C-Terminal Tail Modulate the Function of the Chemokine CCL21'. Together they form a unique fingerprint.

Cite this