InterPro domain: IPR033180

This entry represents type 1 metacaspase from plants, including AtMC1, AtMC2 and AtMC3 from Arabiopsis thaliana. AtMC2 (MEROPS identifier C14.A04) is a cytoplasmic cysteine endopeptidase is a negative regulator of programmed cell death [ 1 ]. It cleaves substrates at arginyl or lysyl bonds, unlike aminal caspases which have a strict requirement for Asp in P1 [ 2 ]. Expression of the AtMC2 gene increases in response to staurosporine, a protein kinase inhibitor that induces apoptosis (Castillo-Olamendi et al., Funct. Plant Biol., 2007).

The Arabidopsis thaliana genome encodes three type I (AtMC1/2/3) and six type II metacaspases (AtMCs). These two types differ in their N-terminal domains. Type 1 metacaspases possess a conserved, plant-specific LSD1-like zinc-finger N-terminal motif (CxxCRxxLMYxxGASxVxCxxC) [ 3 ].

1. Arabidopsis type I metacaspases control cell death. Science 330, 1393-7
2. Two Arabidopsis metacaspases AtMCP1b and AtMCP2b are arginine/lysine-specific cysteine proteases and activate apoptosis-like cell death in yeast. J. Biol. Chem. 280, 14691-9