A Novel Protein Associated with Membrane-type 1 Matrix Metalloproteinase Binds p27 kip1 and Regulates RhoA

on lamellipodia and invadopodia, has to be regulated incoordination with reorganization of the actin cytoskeleton.However, little is known about how such invasion-related actinstructuresareregulatedatthesiteswhereMT1-MMPlocalizes.During analysis of MT1-MMP-associated proteins, we identi-fied a heretofore uncharacterized protein. This protein, whichwe call p27RF-Rho, enhances activation of RhoA by releasing itfrom inhibition by p27