title: Hic-5 mediates the initiation of endothelial sprouting by regulating a key surface metalloproteinase.
abstract: During angiogenesis, endothelial cells must coordinate matrix proteolysis with migration. Here, we tested whether the focal adhesion scaffold protein Hic-5 (also known as TGFB1I1) regulated endothelial sprouting in three dimensions. Hic-5 silencing reduced endothelial sprouting and lumen formation, and sprouting defects were rescued by the return of Hic-5 expression. Pro-angiogenic factors enhanced colocalization and complex formation between membrane type-1 matrix metalloproteinase (MT1-MMP, also known as MMP14) and Hic-5, but not between paxillin and MT1-MMP. The LIM2 and LIM3 domains of Hic-5 were necessary and sufficient for Hic-5 to form a complex with MT1-MMP. The degree of interaction between MT1-MMP and Hic-5 and the localization of the complex within detergent-resistant membrane fractions were enhanced during endothelial sprouting, and Hic-5 depletion lowered the surface levels of MT1-MMP. In addition, we observed that loss of Hic-5 partially reduced complex formation between MT1-MMP and focal adhesion kinase (FAK, also known as PTK2), suggesting that Hic-5 bridges MT1-MMP and FAK. Finally, Hic-5 LIM2-LIM3 deletion mutants reduced sprout initiation. Hic-5, MT1-MMP and FAK colocalized in angiogenic vessels during porcine pregnancy, supporting that this complex assembles during angiogenesis in vivo. Collectively, Hic-5 appears to enhance complex formation between MT1-MMP and FAK in activated endothelial cells, which likely coordinates matrix proteolysis and cell motility.
authors.affiliation: Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843, USA.
authors.forename: Jui M
authors.initials: JM
authors.lastname: Dave
authors.affiliation: Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843, USA.
authors.forename: Colette A
authors.initials: CA
authors.lastname: Abbey
authors.affiliation: Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843, USA.
authors.forename: Camille L
authors.initials: CL
authors.lastname: Duran
authors.affiliation: Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA.
authors.forename: Heewon
authors.initials: H
authors.lastname: Seo
authors.affiliation: Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Johnson
authors.affiliation: Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843, USA kbayless@medicine.tamhsc.edu.
authors.forename: Kayla J
authors.initials: KJ
authors.lastname: Bayless
mesh_terms: D000818:Animals; D002465:Cell Movement; D022081:Cell Surface Extensions / Q000201:enzymology; D002478:Cells, Cultured; D005260:Female; D061307:Human Umbilical Vein Endothelial Cells / Q000201:enzymology* / Q000648:ultrastructure; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000502:physiology*; D060588:LIM Domain Proteins / Q000502:physiology*; D053511:Matrix Metalloproteinase 14 / Q000378:metabolism*; D018919:Neovascularization, Physiologic; D011247:Pregnancy; D054730:Protein Interaction Domains and Motifs; D021381:Protein Transport; D034421:Sus scrofa
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D060588:LIM Domain Proteins; C490351:TGFB1I1 protein, human; D053511:Matrix Metalloproteinase 14
keywords: Angiogenesis; Cell migration; Collagen; Endothelial cell; FAK; LIM; MT1-MMP; Matrix degradation; S1P; Three-dimensional