Related Experiment Videos
Protein-tyrosine phosphatases expressed in mouse epidermal keratinocytes
W Hendriks1, C Brugman, K H Richter
1Department of Cell Biology & Histology, University of Nijmegen, The Netherlands.
Abstract:
The importance of growth factors acting via receptor-type protein-tyrosine kinases in the continuous renewal of the epidermis from the keratinocyte stem cell population has been well established. Protein-tyrosine phosphatases (PTPases), which dephosphorylate phosphotyrosine-containing proteins, may therefore be expected to play an equally important role in the control of epidermal growth and differentiation. In this study, we have made an inventory of the various PTPases that are expressed during mouse keratinocyte proliferation and maturation. A panel of 13 different PTPases probes was obtained by combining a set of PTPase cDNAs previously cloned from mouse brain and a set of PTPase probes obtained from a normalized keratinocyte PTPase cDNA library. This PTPase cDNA panel, spanning probes for receptor-type as well as cytoplasmic-type family members, was used to monitor RNA expression levels in keratinocyte fractions isolated from murine epidermis and in keratinocyte cell cultures. No overt changes were observed in PTPase mRNA levels in all strata of mouse epidermis, but comparison of cultured cells with freshly isolated keratinocytes revealed several conspicuous differences. In the cultured Balb/MK cell line, absence of PTP delta expression and upregulation of PTP kappa and, to a lesser extent, PTP gamma mRNA ratios were observed compared to the freshly isolated cells. These results provide a basis for further research on the impact of PTPase activity on epidermal growth control.
Insights
Protein-tyrosine phosphatases (PTPases) are crucial for epidermal renewal. This study identified PTPase expression in mouse keratinocytes, finding differences between cultured cells and those freshly isolated from epidermis.
Area of Science:
- Cell Biology
- Biochemistry
- Dermatology
Background:
- Growth factors acting via receptor-type protein-tyrosine kinases are vital for epidermal renewal.
- Protein-tyrosine phosphatases (PTPases) dephosphorylate phosphotyrosine-containing proteins and are hypothesized to control epidermal growth and differentiation.
Purpose of the Study:
- To inventory PTPases expressed during mouse keratinocyte proliferation and maturation.
- To investigate the role of PTPase activity in epidermal growth control.
Main Methods:
- Generated a panel of 13 PTPase probes from mouse brain and keratinocyte cDNA libraries.
- Monitored PTPase mRNA expression levels in isolated murine epidermal keratinocytes and cultured keratinocytes.
- Utilized probes for both receptor-type and cytoplasmic-type PTPase family members.
Main Results:
- No significant changes in PTPase mRNA levels were observed across all strata of mouse epidermis.
- Cultured Balb/MK keratinocytes showed absence of PTP delta expression compared to freshly isolated cells.
- Upregulation of PTP kappa and PTP gamma mRNA was observed in cultured Balb/MK cells.
Conclusions:
- PTPase expression patterns differ between freshly isolated and cultured keratinocytes.
- Specific PTPases (PTP delta, kappa, gamma) show altered expression during keratinocyte culture.
- These findings lay the groundwork for future research into PTPase roles in epidermal growth regulation.