Purification and structural characterization of transforming growth factor beta induced protein (TGFBIp) from porcine and human corneas.
Mutations in the TGFBI (BIGH3) gene that encodes for transforming growth factor beta induced protein (TGFBIp) are the cause of several phenotypically different corneal dystrophies. While the genetics of these protein misfolding diseases are well documented, relatively little is known about this extracellular matrix protein itself. In this study, we have purified TGFBIp from normal human and porcine corneas using nondenaturing conditions and standard chromatography techniques. The two homologues were shown to be monomers, and we did not find evidence for posttranslational additions. The C-terminal of both human and porcine TGFBIp is truncated predominantly after the integrin binding sequence Arg(642)-Gly(643)-Asp(644) (RGD). However, using an antibody against the C-terminal fragment (residues 648-683), we also detected a small amount of full-length TGFBIp in corneal extracts. Approximately 60% of TGFBIp was covalently associated with insoluble components of the extracellular matrix in both human and porcine corneas through a disulfide bridge.
Andersen
Rolf B
RB
Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10C, DK 8000 Aarhus C, Denmark.
Karring
Henrik
H
Møller-Pedersen
Torben
T
Valnickova
Zuzana
Z
Thøgersen
Ida B
IB
Hedegaard
Chris J
CJ
Kristensen
Torsten
T
Klintworth
Gordon K
GK
Enghild
Jan J
JJ
D000595:Amino Acid Sequence; D000818:Animals; D002853:Chromatography, Liquid; D003315:Cornea / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D060588:LIM Domain Proteins; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D013552:Swine
D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D060588:LIM Domain Proteins; C490351:TGFB1I1 protein, human