Biochemical analysis of murine Wnt proteins reveals both shared and distinct properties.
The murine Wnt family of proteins consists of at least 12 members that possess significant amino acid homology. Current evidence suggests that these proteins are secreted cell-signaling molecules which are likely to have multiple roles during both embryonic development and oncogenesis. Although the biochemical properties of Wnt-1 have been thoroughly examined, less is known about the characteristics of other Wnt family members. We have compared the properties of six murine Wnt proteins (Wnt-1, Wnt-3a, Wnt-5a, Wnt-5b, Wnt-6, and Wnt-7b) transiently expressed in COS cells. All members enter the endoplasmic reticulum (ER) and are glycosylated. However, all six Wnt proteins are primarily retained in the ER in association with BiP, a resident ER protein that binds to improperly folded proteins and prevents their secretion and/or promotes proper folding. Although all Wnt family members examined are similarly processed, one notable difference was identified. Whereas addition of suramin to COS cell cultures significantly increases the levels of all six Wnts in the medium, the addition of heparin only influences the levels of Wnt-1, Wnt-6, and Wnt-7b.
Burrus
L W
LW
Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
McMahon
A P
AP
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D004721:Endoplasmic Reticulum / Q000378:metabolism; D015870:Gene Expression; D005982:Glutathione Transferase / Q000096:biosynthesis; D006023:Glycoproteins; D051379:Mice; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D051153:Wnt Proteins; D000071818:Wnt-5a Protein; D051155:Wnt1 Protein; D060508:Wnt3 Protein; D060509:Wnt3A Protein; D029961:Zebrafish Proteins
D006023:Glycoproteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; C555510:WNT3A protein, human; C085389:WNT5A protein, human; C490674:WNT6 protein, human; C490675:WNT7B protein, human; D051153:Wnt Proteins; D000071818:Wnt-5a Protein; D051155:Wnt1 Protein; C495246:Wnt1 protein, mouse; D060508:Wnt3 Protein; D060509:Wnt3A Protein; C555511:Wnt3a protein, mouse; C095936:Wnt6 protein, mouse; C095937:Wnt7b protein, mouse; D029961:Zebrafish Proteins; D005982:Glutathione Transferase