An integumentary mucin (FIM-B.1) from Xenopus laevis homologous with von Willebrand factor.
We present a new protein from X. laevis skin termed "frog integumentary mucin B.1" (FIM-B.1) with a general structure similar to FIM-A.1 (formerly "spasmolysin"). The central region consisting of tandem repeats of 11 amino acid residues is probably a target for extensive O-glycosylation, whereas the C-terminal cysteine-rich domain shows pronounced homology with the C1-C2 domains and the C-terminal end of von Willebrand factor. Furthermore, we describe homology with antistasin, an anticoagulant peptide from a leech. We also discuss some implications concerning the evolutionary origin of von Willebrand factor. In situ hybridization studies revealed the expression of FIM-B.1 exclusively in mucous glands of the skin. This is comparable with FIM-A.1 but is in contrast to all other physiologically active peptides, which are synthesized in granular glands.
Max-Planck-Institut für Psychiatrie, Abteilung Neurochemie, Martinsried, FRG.
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JC
Probst
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Gertzen
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Hoffmann
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000235:genetics; D005088:Exocrine Glands / Q000737:chemistry; D006031:Glycosylation; D006801:Humans; D007447:Invertebrate Hormones / Q000235:genetics; D007865:Leeches / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009077:Mucins / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D009093:Mucus; D011499:Protein Processing, Post-Translational; D012091:Repetitive Sequences, Nucleic Acid; D012689:Sequence Homology, Nucleic Acid; D012867:Skin / Q000737:chemistry; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000235:genetics / Q000378:metabolism*; D014841:von Willebrand Factor / Q000235:genetics*
D007447:Invertebrate Hormones; C065866:MUC19 protein, Xenopus; D009077:Mucins; D029867:Xenopus Proteins; D014841:von Willebrand Factor; C053155:antistasin; D004247:DNA