The extracellular human melanoma inhibitory activity (MIA) protein adopts an SH3 domain-like fold

Abstract

Melanoma inhibitory activity (MIA) protein is a clinically valuable marker in patients with malignant melanoma, as enhanced values diagnose metastatic melanoma stages III and IV. Here we show that the recombinant human MIA adopts an SH3 domain-like fold in solution, with two perpendicular, antiparallel, three-and ®ve-stranded b-sheets. In contrast to known structures with the SH3 domain fold, MIA is a single-domain protein, and contains an additional antiparallel b-sheet and two disul®de bonds. MIA is also the ®rst extracellular protein found to have the SH3 domain-like fold. Furthermore, we show that MIA interacts with ®bronectin and that the peptide ligands identi®ed for MIA exhibit a matching sequence to type III human ®bronectin repeats, especially to FN14, which is close to an integrin a 4 b 1 binding site. The present study, therefore, may explain the role of MIA in metastasis in vivo, and supports a model in which the binding of human MIA to type III repeats of ®bronectin competes with integrin binding, thus detaching cells from the extracellular matrix.

Functional role of MIA in melanocytes and early development of melanoma

“…These findings are supported by recent data showing that MIA shares significant structural homologies with the binding pockets of alpha4beta1 and alpha5beta1 integrins, suggesting that secreted MIA masks the respective integrin-binding epitopes on extracellular matrix molecules . These results are consistent with initial findings that MIA expression causes detachment of melanoma cells from the extracellular matrix or cell culture dishes, respectively (Stoll et al, 2001), implicating a model, in which MIA regulates attachment/detachment of melanoma cells and promotes their migratory behavior.…”

“…The corresponding data indicate that MIA defines a novel type of secreted protein, which adopts an SH3 domain-like fold in solution. Furthermore, nuclear magnetic resonance (NMR) spectra revealed that MIA interacts with peptides matching to type III human fibronectin repeats that are closely related to integrinbinding sites (Stoll et al, 2001). These findings are supported by recent data showing that MIA shares significant structural homologies with the binding pockets of alpha4beta1 and alpha5beta1 integrins, suggesting that secreted MIA masks the respective integrin-binding epitopes on extracellular matrix molecules .…”

“…For a deeper insight into the functional properties of MIA, multidimensional NMR (Stoll et al, 2000(Stoll et al, , 2001 and X-ray crystallography (Lougheed et al, 2001) were used to solve the three-dimensional structure of MIA. The corresponding data indicate that MIA defines a novel type of secreted protein, which adopts an SH3 domain-like fold in solution.…”

MIA (melanoma inhibitory activity) promoter mediated tissue-specific suicide gene therapy of malignant melanoma

“…28,31,32 The MIA gene was independently cloned by differential display comparing differentiated and dedifferentiated chondrocytes and has been named cartilage-derived retinoic acid-sensitive protein (CD-RAP). 45 While MIA mediates the detachment of melanoma cells from extracellular matrix molecules such as fibronectin, 26 its expression in non-neoplastic tissues is only activated during the initiation of chondrogenesis throughout cartilage development indicating a highly selective expression pattern of the MIA gene. 31,45 Two different variants, a full-length 1386 bp and a minimal 493 bp MIA promoter fragment were employed to drive selective gene expression.…”

“…MIA plays an important role in melanoma metastasis and invasion. 26,27 and has been identified as a highly specific and sensitive marker for malignant melanoma. [28][29][30] It has been shown that a fragment of approximately 1.4 kb 5 0 flanking DNA of the human gene conferred selective gene expression to melanoma cells, but not to melanocytes.…”