Recombinant Mouse IGFBP-L1 Protein, CF

Insulin-like Growth Factor Binding Protein-Like 1, also known as IGFBP-rP4, is a 38 kDa secreted member of the IGFBP superfamily of proteins. IGFBP superfamily members are cysteine-rich proteins with conserved cysteine residues, which are clustered in the amino- and carboxy-terminal thirds of the molecule. IGFBPs modulate the biological activities of IGF proteins (1). IGFBP-L1 contains an N-terminal IGFBP motif, a Kazal-type serine protease inhibitor region, and a C-terminal Ig-like domain (2, 3). Mature mouse IGFBP-L1 shares 76% and 96% amino acid (aa) sequence identity with human and rat IGFBP-L1, respectively. It shares 38% - 41% aa sequence identity with mouse IGFBP-7 and IGFBP-rp10 and 20% - 24% aa sequence identity with mouse IGFBP-1, -2, -3, -4, -5, and -6. IGFBP-L1 is most highly expressed in testis and brain, while lower levels are more broadly expressed (3). IGFBP-L1 is expressed in regionally and temporally distinct patterns during forebrain development (4). IGFBP-L1 inhibits cell proliferation in vitro and is downregulated in many colon and lung tumors (3). Transcriptional downregulation by promoter methylation is predictive of breast cancer aggressiveness (5).