Recombinant Human Matrilin-2 Protein

Matrilin-2 is an extracellular matrix protein that belongs to the superfamily of von Willebrand factor A (VWA) containing proteins. It is expressed in many tissues and functions as a bridging component between other matrix proteins (1 - 4). The human Matrilin-2 cDNA encodes a 956 amino acid (aa) precursor with a 23 aa signal sequence, two VWA domains separated by ten tandem EGF-like repeats, and a C-terminal coiled-coil domain (5, 6). Alternate splicing generates Isoform 2 (with an 18 aa deletion near the C-terminus), Isoform 3 (with a deletion of the fourth EGF-like repeat), and Isoform 4 (with a deletion of the first VWA and first EGF-like repeat). Human Matrilin-2 shares 87% and 84% aa sequence identity with mouse and canine Matrilin-2, respectively, and 27%, 22%, and 33% aa sequence identity with human Matrilin-1, -3, and -4, respectively. Matrilin-2 forms a variety of disulfide-linked oligomers via its coiled-coil domain (4, 7, 8, 9). It can assemble into homotrimers or heterotrimers with Matrilin-1 and/or Matrilin-4 (4, 7, 8) but has not been detected in heterotrimers containing Matrilin-3 (8). The VWA domains are thought to mediate Matrilin-Matrilin interactions as well as interactions with other matrix proteins such as Fibronectin, Collagen I, Fibrillin-2, and Laminin-1/Nidogen-1 complexes (7). Matrilin-2 knockout mice do not display any obvious abnormalities, suggesting that the expression of other molecules can compensate for the lack of Matrilin-2 (10).