TRAF2 is a component of TNF superfamily signalling complexes and plays an essential role in the regulation and homeostasis of immune cells. TRAF2 deficient mice die around birth, therefore its role in adult tissues is not well-explored. Furthermore, the role of the TRAF2 RING is controversial. It has been claimed that the atypical TRAF2 RING cannot function as a ubiquitin E3 ligase but counterclaimed that TRAF2 RING requires a co-factor, sphingosine-1-phosphate, that is generated by the enzyme sphingosine kinase-1, to function as an E3 ligase. Keratinocyte specific deletion of Traf2, but not Sphk1 deficiency, disrupted TNF mediated NF-κB and MAP kinase signalling and caused epidermal hyperplasia and psoriatic skin inflammation. This inflammation was driven by TNF, cell death, non-canonical NF-κB and the adaptive immune system and might therefore represent a clinically relevant model of psoriasis. TRAF2 therefore has essential tissue specific functions that do not overlap with those of Sphk1.
Animal experimentation: Mice were maintained at the Walter and Eliza Hall Institute (WEHI) under the approval of WEHI ethics committee and Institute guidelines. All procedures were specifcally approved under WEHI Ethics Project Number 2011.013 and 2014.015.
- Ivan Dikic, Goethe University Medical School, Germany
© 2015, Etemadi et al.
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