title: Biotin ligase tagging identifies proteins proximal to E-cadherin, including lipoma preferred partner, a regulator of epithelial cell-cell and cell-substrate adhesion.
abstract: Known proteins associated with the cell-adhesion protein E-cadherin include catenins and proteins involved in signaling, trafficking and actin organization. However, the list of identified adherens junction proteins is likely to be incomplete, limiting investigation into this essential cell structure. To expand the inventory of potentially relevant proteins, we expressed E-cadherin fused to biotin ligase in MDCK epithelial cells, and identified by mass spectrometry neighboring proteins that were biotinylated. The most abundant of the 303 proteins identified were catenins and nearly 40 others that had been previously reported to influence cadherin function. Many others could be rationalized as novel candidates for regulating the adherens junction, cytoskeleton, trafficking or signaling. We further characterized lipoma preferred partner (LPP), which is present at both cell contacts and focal adhesions. Knockdown of LPP demonstrated its requirement for E-cadherin-dependent adhesion and suggested that it plays a role in coordination of the cell-cell and cell-substrate cytoskeletal interactions. The analysis of LPP function demonstrates proof of principle that the proteomic analysis of E-cadherin proximal proteins expands the inventory of components and tools for understanding the function of E-cadherin.
authors: Laboratory of Tight Junction Structure and Function, NHLBI, National Institutes of Health, Bethesda, MD 20892, USA.
authors: Christina M
authors: CM
authors: Van Itallie
authors: Amber Jean
authors: AJ
authors: Tietgens
authors: Angel
authors: A
authors: Aponte
authors: Karin
authors: K
authors: Fredriksson
authors: Alan S
authors: AS
authors: Fanning
authors: Marjan
authors: M
authors: Gucek
authors: James M
authors: JM
authors: Anderson
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D022005:Adherens Junctions / Q000378:metabolism; D000818:Animals; D015703:Antigens, CD; D015820:Cadherins / Q000096:biosynthesis* / Q000235:genetics; D019731:Carbon-Nitrogen Ligases / Q000096:biosynthesis / Q000235:genetics; D002448:Cell Adhesion; D002465:Cell Movement; D004285:Dogs; D004847:Epithelial Cells / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D060588:LIM Domain Proteins / Q000378:metabolism*; D061985:Madin Darby Canine Kidney Cells; D010539:Permeability; D054730:Protein Interaction Domains and Motifs; D025941:Protein Interaction Mapping; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D012097:Repressor Proteins / Q000096:biosynthesis / Q000235:genetics; D013194:Staining and Labeling
chemical_list: D015703:Antigens, CD; C513384:CDH1 protein, human; D015820:Cadherins; D029968:Escherichia coli Proteins; D060588:LIM Domain Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D019731:Carbon-Nitrogen Ligases; C058125:birA protein, E coli
keywords: Adherens junction; Biotin ligase; E-cadherin; Proteomics