Title : The WSAWS
motif is C-hexosylated in a soluble
form of the erythropoietin receptor
Abstract :
- The WSXWS motif is a highly conserved structural feature of the type I cytokine receptor family
- It has previously been demonstrated that mutations in the (232)WSAWS(236) motif in the erythropoietin receptor ( EPOR ) can result in strongly inhibited surface expression, due to defective intracellular transport [Hilton, D. J., et al. (1996) J. Biol
- Chem
- 271, 4699-4708]
- Here we report that the first tryptophan in the motif of the recombinant extracellular domain of EPOR ( sEPOR ) expressed in HEK-EBNA cells carries a C-linked hexosyl residue
- The S233A mutation completely abolished secretion of sEPOR , whereas the A234E mutation resulted in enhanced secretion
- Comparison of the level of C-hexosylation in the wild-type protein and in the mutant proteins isolated from the conditioned medium and/or the cells suggested that C-hexosylation of the motif did not play a role in the correct intracellular transport of sEPOR