Numerous membrane proteins are cleaved by tumor necrosis factor-α converting enzyme （TACE）, which causes the release of their ectodomains. An ADAM （a disintegrin and metalloprotease domain） family member, TACE co...Numerous membrane proteins are cleaved by tumor necrosis factor-α converting enzyme （TACE）, which causes the release of their ectodomains. An ADAM （a disintegrin and metalloprotease domain） family member, TACE contains several noncatalytic domains whose roles in ectodomain shedding have yet to be fully resolved. Here, we have explored the function of the transmembrane domain （TM） of TACE by coupling molecular engineering and functional analysis. A TM-free TACE construct that is anchored to the plasma membrane by a glycosylphosphatidylinositol （GPI）-binding polypeptide failed to restore shedding of transforming growth factor-or （TGF-α）, tumor necrosis factor-α （TNF-α） and L-selectin in cells lacking endogenous TACE activity. Substitution of the TACE TM with that of the prolactin receptor or platelet-derived growth factor receptor （PDGFR） also resulted in severe loss of TGF-α shedding, but had no effects on the cleavage of TNF-α and L-selectin. Replacement of the TM in TGF-α with that of L-selectin enabled TGF-α shedding by the TACE mutants carrying the TM of prolactin receptor and PDGFR. Taken together, our observations suggest that anchorage of TACE to the lipid bilayer through a TM is required for efficient cleavage of a broad spectrum of substrates, and that the amino-acid sequence of TACE TM may play a role in regulatory specificity among TACE substrates.展开更多
Rheumatoid arthritis(RA)is exacerbated by TNF-alpha signaling.However,it remains unclear whether TNF-α-activated TNFR1 and TNFR2 are regulated by extracellular factors.Here,we showed that soluble glycosylated interle...Rheumatoid arthritis(RA)is exacerbated by TNF-alpha signaling.However,it remains unclear whether TNF-α-activated TNFR1 and TNFR2 are regulated by extracellular factors.Here,we showed that soluble glycosylated interleukin-17 receptor D(sIL-17RD),which was produced by proteolytic cleavage,enhanced TNF-α-induced RA.We revealed that IL-17RD shedding was induced by the proteolytic enzyme TACE and enhanced by TNF-αexpression in macrophages.Intriguingly,sIL-17RD was elevated in the sera of arthritic mice and rats.Recombinant sIL-17RD significantly enhanced the TNF-α-induced proinflammatory response by promoting TNF-α-TNFR-sIL-17RD complex formation and receptor clustering,leading to the accelerated development of collagen-induced arthritis.Our observations revealed that ectodomain shedding of IL-17RD occurred in RA to boost the TNF-α-induced inflammatory response.Targeting sIL-17RD may provide a new strategy for the therapy of RA.展开更多
文摘Numerous membrane proteins are cleaved by tumor necrosis factor-α converting enzyme （TACE）, which causes the release of their ectodomains. An ADAM （a disintegrin and metalloprotease domain） family member, TACE contains several noncatalytic domains whose roles in ectodomain shedding have yet to be fully resolved. Here, we have explored the function of the transmembrane domain （TM） of TACE by coupling molecular engineering and functional analysis. A TM-free TACE construct that is anchored to the plasma membrane by a glycosylphosphatidylinositol （GPI）-binding polypeptide failed to restore shedding of transforming growth factor-or （TGF-α）, tumor necrosis factor-α （TNF-α） and L-selectin in cells lacking endogenous TACE activity. Substitution of the TACE TM with that of the prolactin receptor or platelet-derived growth factor receptor （PDGFR） also resulted in severe loss of TGF-α shedding, but had no effects on the cleavage of TNF-α and L-selectin. Replacement of the TM in TGF-α with that of L-selectin enabled TGF-α shedding by the TACE mutants carrying the TM of prolactin receptor and PDGFR. Taken together, our observations suggest that anchorage of TACE to the lipid bilayer through a TM is required for efficient cleavage of a broad spectrum of substrates, and that the amino-acid sequence of TACE TM may play a role in regulatory specificity among TACE substrates.
基金This work was supported by grants from the Chinese National Major Scientific Research Program(2016YFA0500301)from the National Natural Science Foundation of China(NSFC)(81872244,81830092,and 81572729).
文摘Rheumatoid arthritis(RA)is exacerbated by TNF-alpha signaling.However,it remains unclear whether TNF-α-activated TNFR1 and TNFR2 are regulated by extracellular factors.Here,we showed that soluble glycosylated interleukin-17 receptor D(sIL-17RD),which was produced by proteolytic cleavage,enhanced TNF-α-induced RA.We revealed that IL-17RD shedding was induced by the proteolytic enzyme TACE and enhanced by TNF-αexpression in macrophages.Intriguingly,sIL-17RD was elevated in the sera of arthritic mice and rats.Recombinant sIL-17RD significantly enhanced the TNF-α-induced proinflammatory response by promoting TNF-α-TNFR-sIL-17RD complex formation and receptor clustering,leading to the accelerated development of collagen-induced arthritis.Our observations revealed that ectodomain shedding of IL-17RD occurred in RA to boost the TNF-α-induced inflammatory response.Targeting sIL-17RD may provide a new strategy for the therapy of RA.
