SPRY1 and psoriasis: To gain a better understanding of how epidermal SPRY1 negatively regulates the development of psoriasis, we generated K14CreERTSpry1fl/fl mice by crossing mice with loxP-flanked Spry1 alleles (Spry1fl/fl) with keratin 14-Cre/ERT (K14-CreERT) transgenic mice.