Gangliosides play an important role in the organization of CD82-enriched microdomains

Abstract

Four-transmembrane-domain proteins of the tetraspanin superfamily are the organizers of specific microdomains at the membrane [TERMs (tetraspanin-enriched microdomains)] that incorporate various transmembrane receptors and modulate their activities. The structural aspects of the organization of TERM are poorly understood. In the present study, we investigated the role of gangliosides in the assembly and stability of TERM. We demonstrated that inhibition of the glycosphingolipid biosynthetic pathway with specific inhibitors of glucosylceramide synthase [NB-DGJ (N-butyldeoxygalactonojirimycin) and PPMP (D-threo-1-phenyl-2-hexadecanoylamino-3-morpholino-1-propanol · HCl)] resulted in specific weakening of the interactions involving tetraspanin CD82. Furthermore, ectopic expression of the plasmamembrane-bound sialidase Neu3 in mammary epithelial cells also affected stability of the complexes containing CD82: its association with tetraspanin CD151 was decreased, but the association with EGFR [EGF (epidermal growth factor) receptor] was enhanced. The destabilization of the CD82-containing complexes upon ganglioside depletion correlated with the re-distribution of the proteins within plasma membrane. Importantly, depletion of gangliosides affected EGF-induced signalling only in the presence of CD82. Taken together, our results provide strong evidence that gangliosides play an important role in supporting the integrity of CD82-enriched microdomains. Furthermore, these results demonstrate that the association between different tetraspanins in TERM is controlled by distinct mechanisms and identify Neu3 as a first physiological regulator of the integrity of these microdomains.

Role of tetanus neurotoxin insensitive vesicle-associated membrane protein in membrane domains transport and homeostasis

“…16 Tetraspanins are also known to form a specific kind of membrane domains, 46 interact with GSL 18,47 and modulate EGFR signaling. 48 Therefore, TI-VAMPdependent regulation of EGFR may result from its role in transport of components of membrane domains.…”

“…15 More recently, we showed that VAMP7 mediates transport from the Golgi apparatus to the plasma membrane (PM) particularly of tetraspanins 16 which participate in membrane organization 17 and interact with glycosphingolipids. 18 In addition, VAMP7 is involved in the transport of GLUT1 and Lat, two other membrane domain associated proteins. 19,20 Altogether, these findings led us to hypothesize a more direct contribution of VAMP7 in membrane organization and membrane domains homeostasis.…”

Metastasis Suppressor Tetraspanin CD82/KAI1 Regulates Ubiquitylation of Epidermal Growth Factor Receptor

“…Metastasis suppressor tetraspanin CD82/KAI1 has been implicated in the modulation of activities of various transmembrane receptors such as EGFR, c-Met, and ␤1 integrins (5)(6)(7)(8)(9)(10)(11). Specifically, we have previously shown that elevated expression of CD82 in epithelial cells results in the increased internalization rate of EGFR, thus attenuating the signaling of the receptor (5).…”

Identification of the Tetraspanin CD82 as a New Barrier to Xenotransplantation

“…The latter is not expressed in humans (30). The association of CD82 and other tetraspanins with gangliosides is known to modulate cellular signaling (59,60). Whether CD82 on human neutrophils interacts directly with the sialic acid-containing structures on the porcine endothelium remains to be answered.…”