Distinct roles for ROCK1 and ROCK2 in the regulation of keratinocyte differentiation.
BACKGROUND
The human epidermis is comprised of several layers of specialized epithelial cells called keratinocytes. Normal homoeostasis of the epidermis requires that the balance between keratinocyte proliferation and terminal differentiation be tightly regulated. The mammalian serine/threonine kinases (ROCK1 and ROCK2) are well-characterised downstream effectors of the small GTPase RhoA. We have previously demonstrated that the RhoA/ROCK signalling pathway plays an important role in regulation of human keratinocyte proliferation and terminal differentiation. In this paper we addressed the question of which ROCK isoform was involved in regulation of keratinocyte differentiation.


RESULTS
We used RNAi to specifically knockdown ROCK1 or ROCK2 expression in cultured human keratinocytes. ROCK1 depletion results in decreased keratinocyte adhesion to fibronectin and an increase in terminal differentiation. Conversely, ROCK2 depletion results in increased keratinocyte adhesion to fibronectin and inhibits terminal differentiation.


CONCLUSIONS
These data suggest that ROCK1 and ROCK2 play distinct roles in regulating keratinocyte adhesion and terminal differentiation.
Lock
Frances E
FE
School of Biosciences, University of Birmingham, Birmingham, United Kingdom.
Hotchin
Neil A
NA
D002448:Cell Adhesion / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D005353:Fibronectins / Q000494:pharmacology; D055785:Gene Knockdown Techniques; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D015603:Keratinocytes / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D010766:Phosphorylation / Q000187:drug effects; D054460:rho-Associated Kinases / Q000378:metabolism*
D005353:Fibronectins; D007527:Isoenzymes; C515851:ROCK1 protein, human; C515852:ROCK2 protein, human; D054460:rho-Associated Kinases