title: The Wnt/planar cell polarity protein-tyrosine kinase-7 (PTK7) is a highly efficient proteolytic target of membrane type-1 matrix metalloproteinase: implications in cancer and embryogenesis.
abstract: PTK7 is an essential component of the Wnt/planar cell polarity (PCP) pathway. We provide evidence that the Wnt/PCP pathway converges with pericellular proteolysis in both normal development and cancer. Here, we demonstrate that membrane type-1 matrix metalloproteinase (MT1-MMP), a key proinvasive proteinase, functions as a principal sheddase of PTK7. MT1-MMP directly cleaves the exposed PKP(621)↓LI sequence of the seventh Ig-like domain of the full-length membrane PTK7 and generates, as a result, an N-terminal, soluble PTK7 fragment (sPTK7). The enforced expression of membrane PTK7 in cancer cells leads to the actin cytoskeleton reorganization and the inhibition of cell invasion. MT1-MMP silencing and the analysis of the uncleavable L622D PTK7 mutant confirm the significance of MT1-MMP proteolysis of PTK7 in cell functions. Our data also demonstrate that a fine balance between the metalloproteinase activity and PTK7 levels is required for normal development of zebrafish (Danio rerio). Aberration of this balance by the proteinase inhibition or PTK7 silencing results in the PCP-dependent convergent extension defects in the zebrafish. Overall, our data suggest that the MT1-MMP-PTK7 axis plays an important role in both cancer cell invasion and normal embryogenesis in vertebrates. Further insight into these novel mechanisms may promote understanding of directional cell motility and lead to the identification of therapeutics to treat PCP-related developmental disorders and malignancy.
authors.affiliation: Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA.
authors.forename: Vladislav S
authors.initials: VS
authors.lastname: Golubkov
authors.forename: Alexei V
authors.initials: AV
authors.lastname: Chekanov
authors.forename: Piotr
authors.initials: P
authors.lastname: Cieplak
authors.forename: Alexander E
authors.initials: AE
authors.lastname: Aleshin
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Chernov
authors.forename: Wenhong
authors.initials: W
authors.lastname: Zhu
authors.forename: Ilian A
authors.initials: IA
authors.lastname: Radichev
authors.forename: Danhua
authors.initials: D
authors.lastname: Zhang
authors.forename: P Duc
authors.initials: PD
authors.lastname: Dong
authors.forename: Alex Y
authors.initials: AY
authors.lastname: Strongin
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000235:genetics; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D045744:Cell Line, Tumor; D002465:Cell Movement; D016764:Cell Polarity; D003599:Cytoskeleton / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000196:embryology* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D006801:Humans; D017403:In Situ Hybridization; D053511:Matrix Metalloproteinase 14 / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D020794:Receptor Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D014162:Transfection; D051153:Wnt Proteins / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology / Q000235:genetics / Q000378:metabolism; D029961:Zebrafish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D015815:Cell Adhesion Molecules; D051153:Wnt Proteins; D029961:Zebrafish Proteins; C096905:PTK7 protein, human; D020794:Receptor Protein-Tyrosine Kinases; D053511:Matrix Metalloproteinase 14