The membrane-type MMPs (MT-MMPs) MMP14 (MT1-MMP) (Pei et al. 1996, Sato et al. 1996) and MMP16 (MT3-MMP) (Kang et al. 2002) are processed to an active form by furin (Yana & Weiss 2000) and PACE4 (Bassi et al. 2005) within the golgi before secretion. The other MT-MMPs MMP15 (MT2-MMP), MMP17 (MT4-MMP) (Itoh et al. 1999), MMP24 (MT5-MMP) and MMP25 (MT6-MMP) (Starr et al. 2012) are believed to undergo similar processing before membrane association.