This family consists of several plant specific LSD1 zinc finger domains. Arabidopsis lsd1 mutants are hyper-responsive to cell death initiators and fail to limit the extent of cell death. Superoxide is a necessary and sufficient signal for cell death propagation. LSD1 monitors a superoxide-dependent signal and negatively regulates a plant cell death pathway. LSD1 protein contains three zinc finger domains, defined by CxxCxRxxLMYxxGASxVxCxxC. It has been suggested that LSD1 defines a zinc finger protein subclass and that LSD1 regulates transcription, via either repression of a pro-death pathway or activation of an anti-death pathway, in response to signals emanating from cells undergoing pathogen-induced hypersensitive cell death.