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STAT3 deficiency in keratinocytes leads to compromised cell migration through hyperphosphorylation of p130(cas)
Masahiro Kira1, Shigetoshi Sano, Satoshi Takagi
1Department of Dermatology, Course of Molecular Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
Abstract:
We previously reported that STAT3 plays a crucial role in transducing a signal for migration of keratinocytes (Sano, S., Itami, S., Takeda, K., Tarutani, M., Yamaguchi, Y., Miura, H., Yoshikawa, K., Akira, S., and Takeda, J. (1999) EMBO J. 18, 4657-4668). To clarify the role of STAT3 in signaling the migration, we studied the intracellular signaling pathway through an integrin receptor in STAT3-deficient keratinocytes. STAT3-deficient keratinocytes demonstrated increased adhesiveness and fast spreading on a collagen matrix. Staining with anti-phosphotyrosine antibody revealed that STAT3-deficient keratinocytes had an increased number of tyrosyl-hyperphosphorylated focal adhesions. Analyses with immunoprecipitation revealed that p130(cas) was constitutively hyperphosphorylated on tyrosine residues, while other focal adhesion molecules such as focal adhesion kinase and paxillin were not. Transfection of STAT3-deficient keratinocytes with an adenoviral vector encoding the wild-type Stat3 gene reversed not only impaired migration but also the increased tyrosine phosphorylation of p130(cas). These results strongly suggest that STAT3 in keratinocytes plays a critical role in turnover of tyrosine phosphorylation of p130(cas), modulating cell adhesiveness to the substratum leading to growth factor-dependent cell migration.
Insights
Signal transducer and activator of transcription 3 (STAT3) is crucial for keratinocyte migration. STAT3 deficiency increases cell adhesion and focal adhesion phosphorylation, particularly of p130(cas), impacting migration.
Area of Science:
- Cell biology
- Molecular biology
- Dermatology
Background:
- Signal transducer and activator of transcription 3 (STAT3) is essential for keratinocyte migration.
- Understanding the intracellular signaling pathways involved in cell migration is critical.
Purpose of the Study:
- To investigate the role of STAT3 in keratinocyte migration signaling through integrin receptors.
- To elucidate the specific molecular mechanisms by which STAT3 influences cell adhesion and migration.
Main Methods:
- Studied STAT3-deficient keratinocytes to analyze intracellular signaling pathways.
- Utilized anti-phosphotyrosine antibody staining to assess focal adhesions.
- Employed immunoprecipitation to analyze protein phosphorylation, specifically of p130(cas).
- Restored STAT3 function using adenoviral vectors for rescue experiments.
Main Results:
- STAT3-deficient keratinocytes exhibited increased adhesion and spreading on collagen.
- Elevated levels of tyrosyl-phosphorylated focal adhesions were observed in STAT3-deficient cells.
- p130(cas) was constitutively hyperphosphorylated on tyrosine residues, unlike other focal adhesion molecules.
- Restoration of STAT3 reversed impaired migration and p130(cas) hyperphosphorylation.
Conclusions:
- STAT3 plays a critical role in regulating the turnover of p130(cas) tyrosine phosphorylation in keratinocytes.
- STAT3 modulates cell adhesiveness to the substratum, thereby influencing growth factor-dependent cell migration.