Plakoglobin suppresses keratinocyte motility through both cell-cell adhesion-dependent and -independent mechanisms.
Plakoglobin (PG) is a member of the Armadillo family of adhesion/signaling proteins and has been shown to play a critical role in the organization of desmosomes and tissue integrity. Because dissolution of intercellular junctions is frequently an initial step in the onset of epithelial cell migration, we examined whether loss of PG promotes cell motility by compromising adhesive strength. Keratinocyte cultures established from PG-/-mice exhibited weakened adhesion and increased motility in transwell migration assays; both were restored by reintroducing PG through adenoviral infection. Interestingly, single PG-/- cells also exhibited increased motility, which was suppressed by reintroducing PG, but not the closely related beta-catenin. Whereas both N- and C-terminally truncated PG deletion mutants restored adhesion, only N-terminally deleted PG, but not C-terminally deleted PG, suppressed single-cell migration. Furthermore, both the chemical inhibitor PP2 and dominant-negative Src tyrosine kinase inhibited single-cell motility in PG-/- cells, whereas constitutively active Src overcame the inhibitory effect of PG. These data demonstrate that PG strengthens adhesion and suppresses motility in mouse keratinocytes, through both intercellular adhesion-dependent and -independent mechanisms, the latter of which may involve suppression of Src signaling through a mechanism requiring the PG C terminus.
Yin
Taofei
T
Departments of Pathology and Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, 303 East Chicago Avenue, Chicago, IL 60611, USA.
Getsios
Spiro
S
Caldelari
Reto
R
Kowalczyk
Andrew P
AP
Müller
Eliane J
EJ
Jones
Jonathan C R
JC
Green
Kathleen J
KJ
D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051180:Desmoplakins; D015603:Keratinocytes / Q000166:cytology* / Q000378:metabolism*; D051379:Mice; D017434:Protein Structure, Tertiary; D017384:Sequence Deletion / Q000235:genetics; D051185:gamma Catenin; D019061:src-Family Kinases / Q000378:metabolism
D003598:Cytoskeletal Proteins; D051180:Desmoplakins; D051185:gamma Catenin; D019061:src-Family Kinases; D002118:Calcium