Background：

This gene is a member of the TIMP gene family. The proteins encoded by this gene family are natural inhibitors of the matrix metalloproteinases， a group of peptidases involved in degradation of the extracellular matrix. In addition to an inhibitory role against metalloproteinases， the encoded protein has a unique role among TIMP family members in its ability to directly suppress the proliferation of endothelial cells. As a result， the encoded protein may be critical to the maintenance of tissue homeostasis by suppressing the proliferation of quiescent tissues in response to angiogenic factors， and by inhibiting protease activity in tissues undergoing remodelling of the extracellular matrix.