The TNF receptor (TNFR) associated factor (TRAF) protein family is characterized by the presence of a conserved coiled-coil domain TRAF/MATH domain (for meprin and TRAF-C homology).  Typically, TRAFs are characterized by a TRAF domain at the C-terminal region, containing about 180 amino acids that form a fold of seven to eight anti-parallel β-strands that regulate protein processing and interaction. The TRAF domain is required for homo- or heterodimerization and interaction with receptor or cytoplasmic signaling proteins including transcription factors (TFs) (Ye et al., 1999, Park et al., 1999, Zheng et al., 2010, Dai et al., 2023).  

This family of proteins is present in plants but the biological role of relatively few plant TRAF proteins have been characterized. In Brassica rapa, MATH proteins have been grouped into six classes, whereas, in Arabidopsis thaliana and rice (Oryza sativa), they have been mainly clustered into four distinct groups, including MATH-only proteins, MATH-BPM proteins, MATH-UBP proteins, and MATH-PEARLI-4 proteins (Qi et al., 2021).

There are about 31 MATH-BTB (for BR-C, ttk and bab) genes in the maize (Zea mays) genome (Juranič et al., 2012). One of these maize proteins, MAB1 (ZmTRAF1), was was shown to be specifically expressed in both germ lineages and the zygote, and has been shown to regulate spindle length during meiosis as well as nuclei identity during the first asymmetric pollen mitosis (Juranič et al., 2012). A wider phylogenetic analysis of the expansion of the MATH-BTB gene family in the grasses reported that just 6 homologous genes in the model plant Arabidopsis while there is a general increase in grass lineages (Juranič et al., 2014).  In Arabidopsis the SEVEN IN ABSENTIA (SINA) clade of TRAF-like proteins has been implicated in proteasome-mediated regulation of transcription factors such as NAC1, CUC2, and AP2.  In rice, OsDIS1 has been identified as a negative regulator in the drought tolerance response.  Another study revealed that MATH-Domain Family members show a response toward abiotic stress in both Arabidopsis and Rice (Kushwaha et al., 2016)

Last updated June 2023 by John Gray

References:

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Kushwaha HR, Joshi R, Pareek A, Singla-Pareek SL. MATH-Domain Family Shows Response toward Abiotic Stress in Arabidopsis and Rice. Front Plant Sci. 2016 Jun 28;7:923. doi: 10.3389/fpls.2016.00923. PMID: 27446153; PMCID: PMC4923191.