- Activation of protein kinase CK2 is an early step in the ultraviolet B-mediated increase in interstitial collagenase (matrix metalloproteinase-1; MMP-1) and stromelysin-1 (MMP-3) protein levels in human dermal fibroblasts. Brenneisen, P., Wlaschek, M., Schwamborn, E., Schneider, L.A., Ma, W., Sies, H., Scharffetter-Kochanek, K. Biochem. J. (2002)