Metalloprotease‐mediated cleavage of CD95 ligand

CD95 is a member of the TNF receptor superfamily that is ubiquitously expressed in healthy and pathological tissues. Stimulation of CD95 by its physiological ligand CD95L induces its oligomerization leading in turn to the transduction of either apoptotic or nonapoptotic signals. CD95L can exist as both membrane‐anchored and soluble forms (sCD95L), the latter resulting from the proteolytic cleavage of the former. Candidate proteases able to achieve CD95L cleavage were identified as matrix metalloproteases (MMP) due to their demonstrated ability to cleave other TNF superfamily ligands. The main goal of this study was to systematically identify the MMP family members capable of cleaving CD95L and subsequently determine the corresponding cleavage sites. By using different orthogonal biochemical approaches and combining them with molecular modelling, we confirmed data from the literature regarding CD95L cleavage by MMP‐3 and MMP‐7. Moreover, we found that MMP‐2 and MMP‐12 can cleave CD95L and characterized their resulting cleavage sites. This study provides a systematic approach to analyse the cleavage of CD95L, which until now had only been poorly described. CD95 and its ligand CD95L were first described for their implication in extrinsic apoptotic signal transmission. The extracellular domain of CD95L can be proteolytically cleaved through the action of metalloproteases. Releasing a trimeric soluble CD95L can trigger non‐apoptotic signalling cascades. High serum levels of sCD95L have been detected in patients with various pathologies. This study aimed to systematically identify the proteases capable of cleaving CD95L and subsequently determine the corresponding cleavage sites.