TspanC8 Tetraspanins and A Disintegrin and Metalloprotease 10 (ADAM10) Interact via Their Extracellular Regions

Abstract

A disintegrin and metalloprotease 10 (ADAM10) is a ubiquitously expressed transmembrane metalloprotease that cleaves the extracellular regions from its transmembrane substrates. ADAM10 is essential for embryonic development and is implicated in cancer, Alzheimer, and inflammatory diseases. The tetraspanins are a superfamily of 33 four-transmembrane proteins in mammals, of which the TspanC8 subgroup (Tspan5, 10, 14, 15, 17, and 33) promote ADAM10 intracellular trafficking and enzymatic maturation. However, the interaction between TspanC8s and ADAM10 has only been demonstrated in overexpression systems and the interaction mechanism remains undefined. To address these issues, an antibody was developed to Tspan14, which was used to show co-immunoprecipitation of Tspan14 with ADAM10 in primary human cells. Chimeric Tspan14 constructs demonstrated that the large extracellular loop of Tspan14 mediated its co-immunoprecipitation with ADAM10, and promoted ADAM10 maturation and trafficking to the cell surface. Chimeric ADAM10 constructs showed that membrane-proximal stalk, cysteine-rich, and disintegrin domains of ADAM10 mediated its co-immunoprecipitation with Tspan14 and other TspanC8s. This TspanC8-interacting region was required for ADAM10 exit from the endoplasmic reticulum. Truncated ADAM10 constructs revealed differential TspanC8 binding requirements for the stalk, cysteine-rich, and disintegrin domains. Moreover, Tspan15was the only TspanC8 to promote cleavage of the ADAM10 substrate N-cadherin, whereas Tspan14 was unique in reducing cleavage of the platelet collagen receptor GPVI. These findings suggest that ADAM10 may adopt distinct conformations in complex with different TspanC8s, which could impact on substrate selectivity. Furthermore, this study identifies regions of TspanC8s and ADAM10 for potential interaction-disrupting therapeutic targeting.

Structural Basis for Regulated Proteolysis by the α-Secretase ADAM10

“…Of note, the cysteine-rich domain of all human ADAMs contains a variable sized loop of 27-55 amino acids with low sequence homology to other ADAM family proteins called the hyper-variable region (HVR), which may be critical for substrate engagement. Alternatively, association of the ADAM10 disintegrin-cysteine rich region with members of the C8 family of tetraspanin proteins has been reported to facilitate ADAM10 export to the cell surface, enhancing its ability to process substrates (Dornier et al, 2012; Jouannet et al, 2016; Noy et al, 2016). Whether the dominant-negative effect arises from competitive trans association with fully unmasked metalloprotease active sites, from competition for substrate, or from competition for binding sites on proteins associated with ADAM10 transport, such as the C8-family of tetraspanin proteins, remains to be determined.…”

Staphylococcus aureus pore-forming toxins: The interface of pathogen and host complexity

“…Notably, the enzymatic activity of ADAM10 is not necessary for Hla-binding [116]. Maturation and surface expression of ADAM10 is regulated by the members of the TspanC8 family of proteins [125, 126], including Tetraspanin-14 and −33 [114, 115]. Thus, factors that regulate ADAM10 surface expression also regulate the Hla susceptibility [115].…”

Crystal Structure of a Full-Length Human Tetraspanin Reveals a Cholesterol-Binding Pocket

“…There is accumulating evidence that the six tetraspanins in the C8 subclass regulate Notch signaling by promoting ADAM10 trafficking and enzymatic maturation in both flies and mammals (Dornier et al, 2012; Haining et al, 2012; Jouannet et al, 2016; Noy et al, 2016). A number of other tetraspanins appear to exert their effects by influencing integrin signaling, either indirectly by modulating responses of integrins to their ligands (van Spriel et al, 2012; Wee et al, 2015), or by directly and stably associating with particular integrin heterodimers (Yauch et al, 1998).…”