Epithelial cells assemble adhesive and communicating cell junctions at substrate and cell-cell contacts. In epidermis, cell junctions integrate individual keratinocytes into tissue with barrier and communicating functions. Quiescent keratinocytes anchor to laminin 5 in the basement membrane (BM) via integrin a6134 in hemidesmosomes (HD) and integrin alpha-3beta-1 in focal adhesions (FAs). Cell-cell interactions are mediated by at least three types of intercellular junctions: adherens junctions (AJs), desmosomes and gap junctions (GJs). Connexin 43 (Cx43) is the predominant constituent of GJs in the epidermis. Wounding of quiescent epidermis disrupts cell junctions and activates migration of an epidermal cell outgrowth over exposed dermal collagen and fibronectin with deposition of laminin 5 in repair of the BM. The outgrowth contains both leading and following keratinocytes that are distinct based on substrate ligands, integrin adhesion, cell signaling, and GJs. We have identified a form of communication between adhesive and cell-cell junctions in the epidermis and have suggested two hypotheses based on our findings. We hypothesize that PI3K-dependent adhesion on laminin 5, but not Rho-dependent adhesion on collagen, promotes assembly of GJs. Second, that cell confluence in quiescent tissues inhibits adhesion to collagen and fibronectin but does not inhibit adhesion to BM laminin 5. We propose to test these hypotheses in two steps: 1. Map components and structures that link communication between laminin 5 and GJs in the following keratinocytes. 2. Elucidate the mechanisms that these components utilize to affect adhesion and junctional communication. These studies will provide an understanding of components and mechanisms critical for regulating epithelial morphogenesis in development, wound repair and tumor invasion.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR047963-02
Application #
6512130
Study Section
General Medicine A Subcommittee 2 (GMA)
Program Officer
Moshell, Alan N
Project Start
2001-08-15
Project End
2006-05-31
Budget Start
2002-06-01
Budget End
2003-05-31
Support Year
2
Fiscal Year
2002
Total Cost
$410,875
Indirect Cost
Name
Fred Hutchinson Cancer Research Center
Department
Type
DUNS #
075524595
City
Seattle
State
WA
Country
United States
Zip Code
98109
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Solan, Joell L; Lampe, Paul D (2008) Connexin 43 in LA-25 cells with active v-src is phosphorylated on Y247, Y265, S262, S279/282, and S368 via multiple signaling pathways. Cell Commun Adhes 15:75-84
Singh, Deepika; Solan, Joell L; Taffet, Steven M et al. (2005) Connexin 43 interacts with zona occludens-1 and -2 proteins in a cell cycle stage-specific manner. J Biol Chem 280:30416-21
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King, Timothy J; Lampe, Paul D (2005) Altered tumor biology and tumorigenesis in irradiated and chemical carcinogen-treated single and combined connexin32/p27Kip1-deficient mice. Cell Commun Adhes 12:293-305
King, Timothy J; Lampe, Paul D (2004) Mice deficient for the gap junction protein Connexin32 exhibit increased radiation-induced tumorigenesis associated with elevated mitogen-activated protein kinase (p44/Erk1, p42/Erk2) activation. Carcinogenesis 25:669-80
King, Timothy J; Lampe, Paul D (2004) The gap junction protein connexin32 is a mouse lung tumor suppressor. Cancer Res 64:7191-6
Richards, Theresa S; Dunn, Clarence A; Carter, William G et al. (2004) Protein kinase C spatially and temporally regulates gap junctional communication during human wound repair via phosphorylation of connexin43 on serine368. J Cell Biol 167:555-62
Brown, Tod A; Yang, Tai Mei; Zaitsevskaia, Tatiana et al. (2004) Adhesion or plasmin regulates tyrosine phosphorylation of a novel membrane glycoprotein p80/gp140/CUB domain-containing protein 1 in epithelia. J Biol Chem 279:14772-83
Singh, Deepika; Lampe, Paul D (2003) Identification of connexin-43 interacting proteins. Cell Commun Adhes 10:215-20

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