Precise Mapping of the CD95 Pre-Ligand Assembly Domain

Valérie Edmond,Patrick Legembre,Jean-Luc Taupin,Sophie Daburon,Aubin Penna,Benoist Ghali,Jean-François Moreau

doi:10.1371/journal.pone.0046236

Abstract

Pre-association of CD95 at the plasma membrane is mandatory for efficient death receptor signaling. This homotrimerization occurs through self-association of an extracellular domain called the pre-ligand assembly domain (PLAD). Using novel molecular and cellular tools, we confirmed that CD95-PLAD is necessary to promote CD95 multimerization and plays a pivotal role in the transmission of apoptotic signals. However, while a human CD95 mutant deleted of the previously described PLAD domain (amino acids 1 to 66) fails to interact with its wild-type counterpart and trigger autonomous cell death, deletion of amino acids 1 to 42 does not prevent homo- or hetero (human/mouse)-oligomerization of CD95, and thus does not alter transmission of the apoptotic signal. Overall, these findings indicate that the region between amino acids 43 to 66 corresponds to the minimal motif involved in CD95 homotypic interaction and is necessary to convey an efficient apoptotic signal. Interfering with this PLAD may represent a new therapeutic strategy for altering CD95-induced apoptotic and non-apoptotic signals.

Highlights

Despite their pleiotropic effects, ranging from apoptosis to cell proliferation, members of the TNF (Tumor Necrosis Factor)receptor family share remarkably similar structures and modes of interaction and aggregation, indicating that subtle differences may account for the transmission of different signaling pathways
This indicates that the first sub-domain of CRD1 encompasses a minimal homotypic interaction domain termed PLAD for pre-ligand assembly domain [7] that contributes to self-association of the receptor [7,9]
A key feature of this receptor is that its intracellular domain is pre-associated with Janus kinases (i.e., Jak1, Jak2 and Tyk2), whose close proximity is required for activation by trans-phosphorylation and the induction of STAT1/3-mediated pro-proliferative and survival pathways [20]

Summary

Introduction

Despite their pleiotropic effects, ranging from apoptosis to cell proliferation, members of the TNF (Tumor Necrosis Factor)receptor family share remarkably similar structures and modes of interaction and aggregation, indicating that subtle differences may account for the transmission of different signaling pathways. These cells were transiently transfected to express either gp130 devoid of the extracellular domain (DExtra-gp130) [12] or the ectodomain of CD95 fused to the transmembrane and intracellular regions of gp130 (CD95-gp130) (Fig. 1A).

Results

Conclusion