Intermediate filament-membrane attachments function synergistically with actin-dependent contacts to regulate intercellular adhesive strength.
By tethering intermediate filaments (IFs) to sites of intercellular adhesion, desmosomes facilitate formation of a supercellular scaffold that imparts mechanical strength to a tissue. However, the role IF-membrane attachments play in strengthening adhesion has not been directly examined. To address this question, we generated Tet-On A431 cells inducibly expressing a desmoplakin (DP) mutant lacking the rod and IF-binding domains (DPNTP). DPNTP localized to the plasma membrane and led to dissociation of IFs from the junctional plaque, without altering total or cell surface distribution of adherens junction or desmosomal proteins. However, a specific decrease in the detergent-insoluble pool of desmoglein suggested a reduced association with the IF cytoskeleton. DPNTP-expressing cell aggregates in suspension or substrate-released cell sheets readily dissociated when subjected to mechanical stress whereas controls remained largely intact. Dissociation occurred without lactate dehydrogenase release, suggesting that loss of tissue integrity was due to reduced adhesion rather than increased cytolysis. JD-1 cells from a patient with a DP COOH-terminal truncation were also more weakly adherent compared with normal keratinocytes. When used in combination with DPNTP, latrunculin A, which disassembles actin filaments and disrupts adherens junctions, led to dissociation up to an order of magnitude greater than either treatment alone. These data provide direct in vitro evidence that IF-membrane attachments regulate adhesive strength and suggest furthermore that actin- and IF-based junctions act synergistically to strengthen adhesion.
Huen
Arthur C
AC
Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
Park
Jung K
JK
Godsel
Lisa M
LM
Chen
Xuejun
X
Bannon
Leslie J
LJ
Amargo
Evangeline V
EV
Hudson
Tracie Y
TY
Mongiu
Anne K
AK
Leigh
Irene M
IM
Kelsell
David P
DP
Gumbiner
Barry M
BM
Green
Kathleen J
KJ
D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D019921:Biotinylation; D015820:Cadherins / Q000378:metabolism; D002448:Cell Adhesion; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000235:genetics; D003599:Cytoskeleton / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D051182:Desmogleins; D051180:Desmoplakins; D003896:Desmosomes / Q000378:metabolism; D003902:Detergents / Q000494:pharmacology; D049452:Green Fluorescent Proteins; D006801:Humans; D007382:Intermediate Filaments / Q000378:metabolism*; D015603:Keratinocytes / Q000378:metabolism; D007645:Keratoderma, Palmoplantar / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D013997:Time Factors; D014162:Transfection; D014407:Tumor Cells, Cultured
D000199:Actins; D015820:Cadherins; D003598:Cytoskeletal Proteins; D018076:DNA, Complementary; C495294:DSP protein, human; D051182:Desmogleins; D051180:Desmoplakins; D003902:Detergents; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; D007770:L-Lactate Dehydrogenase