描述:
Dickkopf related protein 4 (Dkk-4) is a member of the Dickkopf protein family that includes
Dkk-1, -2, -3, and -4 and a related protein, Soggy. Expression of Dkk-4 has only been shown
with sensitive PCR techniques during early embryonic development in mice, in differentiated
human ES cells, or in mice that express dominantactive βcatenin elevating Wnt signaling
in the forebrain. Dkk proteins are secreted proteins that are synthesized as precursors with
an Nterminal signal peptide; all have two conserved cysteinerich domains separated by a
linker region which contains a potential furin type proteolytic cleavage site. The domains
contain 10 cysteines each; prokineticin and colipase families show a configuration of
cysteines similar to the second motif. Mouse Dkk-4 shows 91%, 72% and 71% amino acid (aa)
identity with rat, human and canine Dkk-4, respectively, and 40-46% aa identity with other
mouse Dkk proteins. Dkk-4 is predicted as a 25 kDa protein, but transfection of 293T cells
produces a shorter (15-17 kDa) form containing only the second cysteinerich domain, as well
as longer (30-32 and 40 kDa) forms that do not appear to be glycosylated or form covalent
multimers. Of the four Dkk proteins, Dkk-4 is the most like Dkk-1. Both are unequivocal
antagonists of the canonical Wnt signaling pathway, which is activated by Wnt protein
engagement of a receptor complex composed of the Frizzled proteins and one of two
lowdensity lipoprotein receptorrelated proteins, LRP5 or LRP6. Dkk1 and Dkk-4 antagonize
Wnt by direct highaffinity binding to LRP5/6, forming ternary complexes of LRP5/6 with the
Kremens protein Krm2. Internalization of the complex is triggered, making LRP5/6 unavailable
for interaction with Wnt ligands.
原厂资料:
Dickkopf related protein 4 (Dkk-4) is a member of the Dickkopf protein family that includes
Dkk-1, -2, -3, and -4 and a related protein, Soggy. Expression of Dkk-4 has only been shown
with sensitive PCR techniques during early embryonic development in mice, in differentiated
human ES cells, or in mice that express dominantactive βcatenin elevating Wnt signaling
in the forebrain. Dkk proteins are secreted proteins that are synthesized as precursors with
an Nterminal signal peptide; all have two conserved cysteinerich domains separated by a
linker region which contains a potential furin type proteolytic cleavage site. The domains
contain 10 cysteines each; prokineticin and colipase families show a configuration of
cysteines similar to the second motif. Mouse Dkk-4 shows 91%, 72% and 71% amino acid (aa)
identity with rat, human and canine Dkk-4, respectively, and 40-46% aa identity with other
mouse Dkk proteins. Dkk-4 is predicted as a 25 kDa protein, but transfection of 293T cells
produces a shorter (15-17 kDa) form containing only the second cysteinerich domain, as well
as longer (30-32 and 40 kDa) forms that do not appear to be glycosylated or form covalent
multimers. Of the four Dkk proteins, Dkk-4 is the most like Dkk-1. Both are unequivocal
antagonists of the canonical Wnt signaling pathway, which is activated by Wnt protein
engagement of a receptor complex composed of the Frizzled proteins and one of two
lowdensity lipoprotein receptorrelated proteins, LRP5 or LRP6. Dkk1 and Dkk-4 antagonize
Wnt by direct highaffinity binding to LRP5/6, forming ternary complexes of LRP5/6 with the
Kremens protein Krm2. Internalization of the complex is triggered, making LRP5/6 unavailable
for interaction with Wnt ligands.