BPAG1e maintains keratinocyte polarity through beta4 integrin-mediated modulation of Rac1 and cofilin activities.
alpha6beta4 integrin, a component of hemidesmosomes, also plays a role in keratinocyte migration via signaling through Rac1 to the actin-severing protein cofilin. Here, we tested the hypothesis that the beta4 integrin-associated plakin protein, bullous pemphigoid antigen 1e (BPAG1e) functions as a scaffold for Rac1/cofilin signal transduction. We generated keratinocyte lines exhibiting a stable knockdown in BPAG1e expression. Knockdown of BPAG1e does not affect expression levels of other hemidesmosomal proteins, nor the amount of beta4 integrin expressed at the cell surface. However, the amount of Rac1 associating with beta4 integrin and the activity of both Rac1 and cofilin are significantly lower in BPAG1e-deficient cells compared with wild-type keratinocytes. In addition, keratinocytes deficient in BPAG1e exhibit loss of front-to-rear polarity and display aberrant motility. These defects are rescued by inducing expression of constitutively active Rac1 or active cofilin. These data indicate that the BPAG1e is required for efficient regulation of keratinocyte polarity and migration by determining the activation of Rac1.
Hamill
Kevin J
KJ
Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, IL 60611, USA.
Hopkinson
Susan B
SB
DeBiase
Philip
P
Jones
Jonathan C R
JC
D051339:Actin Depolymerizing Factors / Q000378:metabolism*; D000199:Actins / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D002465:Cell Movement; D016764:Cell Polarity; D003598:Cytoskeletal Proteins / Q000172:deficiency / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D000071821:Dystonin; D004789:Enzyme Activation; D000078404:Epidermal Cells; D022001:Focal Adhesions / Q000378:metabolism; D055785:Gene Knockdown Techniques; D006801:Humans; D039663:Integrin beta4 / Q000378:metabolism*; D015603:Keratinocytes / Q000166:cytology* / Q000378:metabolism*; D016086:Lentivirus / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000172:deficiency / Q000378:metabolism*; D051190:Plectin / Q000378:metabolism; D021381:Protein Transport; D011554:Pseudopodia / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000378:metabolism*
D051339:Actin Depolymerizing Factors; D000199:Actins; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; C486268:DST protein, human; D000071821:Dystonin; D039663:Integrin beta4; D009419:Nerve Tissue Proteins; D051190:Plectin; D034741:RNA, Small Interfering; D020830:rac1 GTP-Binding Protein