the qcm gelatin invadopodia assays were performed and quantified according to manufacturer instructions ( millipore , ecm670 ) . in each experiment the total number of degradation spots formed after 20 h incubation ( including both invadopodia and other protrusive membrane structures ) was quantified from three independent experiments ( 12 images per experiment = 36 fields of view analyzed , > 500 cells per condition ) . the number of invadopodia formed after 5  h was also quantified from three independent experiments ( 20 cells per experiment = 60 total cells per condition ) . only cells with at least one invadopodium were analyzed . cortactin antibody labeling ( millipore clone 4f11 ; 1:500 dilution ) was detected using a mouse cy5 secondary antibody ( jackson immunoresearch ; 1:400 dilution ) .
understanding how planar cell polarity ( pcp ) is established , maintained , and coordinated in migrating cell populations is an important area of research with implications for both embryonic morphogenesis and tumor cell invasion . 
 we recently reported that the pcp protein vang - like 2 ( vangl2 ) regulates the endocytosis and cell surface level of membrane type-1 matrix metalloproteinase ( mmp14 or mt1-mmp ) . here 
 , we further discuss these findings in terms of extracellular matrix ( ecm ) remodeling , cell migration , and zebrafish gastrulation . 
 we also demonstrate that vangl2 function impacts the focal degradation of ecm by human cancer cells including the formation or stability of invadopodia . 
 together , our findings implicate mmp14 as a downstream effector of vangl2 signaling and suggest a model whereby the regulation of pericellular proteolysis is a fundamental aspect of pcp in migrating cells .