Alternate trafficking of cathepsin L in dermal fibroblasts induced by UVA radiation

Anke Klose*, Astrid Wilbrand-Hennes, Jürgen Brinckmann, Nicolas Hunzelmann

*Corresponding author for this work
7 Citations (Scopus)


UVA radiation is increasingly used to treat fibrotic skin disorders. However, the mechanisms underlying the therapeutic effects of UVA for these disorders are only partially understood. Cathepsin L is a lysosomal cysteine protease, which has been shown to degrade various matrix proteins thus contributing to extracellular remodeling. Therefore, we investigated whether UVA irradiation regulates the expression and release of cathepsin L in human dermal fibroblasts. No alterations were found after single irradiation; however, a significantly increased extracellular release of cathepsin L was observed after repeated irradiation up to four times. The transcript levels of cathepsin L were elevated after repetitive irradiation, leading to increased amounts of total cathepsin L protein. Furthermore, higher amounts of extracellular cathepsin L were associated with a significant reduction of intracellular processed cathepsin L and an accumulation of unprocessed procathepsin L. The use of specific inhibitors elucidated mannose phosphate-independent sorting pathways of cathepsin L leading to enhanced secretion and reduced intracellular processing. This is the first study which demonstrates that alternate trafficking mechanisms mediate the extracellular release of a cysteine protease induced by repetitive UVA irradiation.

Original languageEnglish
JournalExperimental Dermatology
Issue number8
Publication statusPublished - 01.08.2010

Research Areas and Centers

  • Academic Focus: Center for Infection and Inflammation Research (ZIEL)


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