Engineering of tissue inhibitor of metalloproteinases mutants as potential therapeutics

Abstract

Matrix metalloproteinases (MMPs) play a central role in many biological processes such as development, morphogenesis and wound healing, but their unbalanced activities are implicated in numerous disease processes such as arthritis, cancer metastasis, atherosclerosis, nephritis and fibrosis. One of the key mechanisms to control MMP activities is inhibition by endogenous inhibitors called tissue inhibitors of metalloproteinases (TIMPs). This review highlights the structures and inhibition mechanism of TIMPs, the biological activities of TIMPs, the unique properties of TIMP-3, and the altered specificity towards MMPs achieved by mutagenesis. A potential therapeutic use of TIMP variants is discussed.

Figure 1

A ribbon diagram of tissue inhibitor of metalloproteinases 1 (TIMP-1) bound to the catalytic domain of matrix metalloproteinase 3 [MMP-3 (ΔC)]. TIMP-1 is shown in green and MMP-3 (ΔC) is shown in light brown. Cystines, Thr2, Val4 and Ser68 in TIMP-1 are indicated: N, blue; O, red; C, grey; and disulfide bonds, yellow. Strands and helices in TIMP-1 are labelled A–J and 1–4, respectively. The catalytic and structural zinc ions are shown in purple, and calcium ions are shown in orange. The image was prepared from the Brookhaven Protein Data Bank entry (1UEA) using the Swiss PDB viewer [91].

Figure 2

A schematic display of the secondary structure of tissue inhibitor of metalloproteinases 1 (TIMP-1). The crystal structure of TIMP-1 was determined as a complex with the catalytic domain of MMP-3 [86]. Strands (A–J) and helices (H1–H4) are shown. Two glycosylation sites are indicated by diamonds.

Figure 3

A schematic representation of (a) the N-terminal region of tissue inhibitor of metalloproteinases 1 (TIMP-1) and (b) a peptidyl-hydroxamate inhibitor. The scheme of TIMP-1 is based on the crystal structure of the TIMP-1-MMP-3(ΔC) complex [86].

Figure 4

The surface structure of tissue inhibitor of metalloproteinases 1 (TIMP-1). The N-terminal domain and the C-terminal domain are shown in light red and green, respectively. The region within 4 Å contact with the matrix metalloproteinase (MMP) catalytic domain is shown in blue. Mutation sites coloured red modulate the selectivity of N-TIMP-1 against different MMPs. The image was prepared from the Brookhaven Protein Data Bank entry (1UEA) using the Swiss PDB viewer [91].