The collaboration of MTP with MMPs on NP cell mobility. A, non-transfected (NONE), MTP siRNA-transfected (MTP KD), or MTP expression plasmid-transfected (MTP OV) NP cells were treated with 10 or 20 μm MMP inhibitor (GM6001). Cell mobility was assayed in transwells. B, RT-PCR of MTP (lane a), MMP2 (lane b), MMP3 (lane c), and MMP9 (lane d) in Sox1-GFP+ NP cells. Lane e is S15 as control. C, RT-PCR assay of MTP and MMP2 in cells treated with specific siRNA for MMP2 knockdown (lane b), MTP knockdown (lane c), and MMP2-MTP double knockdown (lane d). Lane a shows cells without siRNA and lane e shows cells treated with a no-target control siRNA. S15 is the internal loading control. D, mobility of the control untreated NP cells (CTRL), NP cells transfected with the non-silencing siRNA (siNeg), MMP2-specific siRNA (siMMP2), MTP-specific siRNA (siMTP), or the combined siRNAs of both MMP2 and MTP (siMMP2+siMTP). E, the recombinant pro-MMP2 protein was incubated overnight at room temperature with buffer (NO), with cell lysate of NP cells (CT), lysates of NP cells transfected with MTP siRNA (KD), or lysates of NP cells transfected with MTP-expressing plasmid (OV) followed by Western immunoblotting with anti-MMP2 antibody. All lanes were assembled from samples on the same Western blot membrane. *, p < 0.05.