Figure 2. The subunit composition of the COMPASS family from yeast to human.

The yeast Set1/COMPASS is the founding member of the family of COMPASS H3K4 methyltransferases. There is only one Set1/COMPASS in yeast capable of methylating histone H3 on its fourth lysine (H3K4). From yeast to Drosophila, COMPASS is divided into three family members. The Set1/COMPASS of Drosophila is the direct descendent of the yeast Set1 complex (shown by solid arrow). There are two COMPASS-like complexes in Drosophila (shown by dotted arrow); one Trithorax (trx)-containing complex and the other Trithorax-related-containing complex (trr). The SET domain-containing enzymes from yeast to Drosophila are shown in RED, and the conserved subunits between yeast and Drosophila are shown in GREEN. The complex specifics are shown in BLUE and PURPLE. From Drosophila to human cells, the COMPASS family is divided into six members. The mammalian Set1A and B are direct homologs of yeast and Drosophila Set1 and are found in Set1A-B/COMPASS (shown by solid arrow). The subunit composition and function of Trx of Drosophila is divided between MLL1 and MLL2 in the mammalian cells. Both MLL1 and MLL2 are found in COMPASS-like complexes. The subunit composition and function of Trr of Drosophila is divided between MLL3 and MLL4 in the mammalian cells, both of which are also found in COMPASS-like complexes. All six mammalian COMPASS family members are capable of methylating H3K4. The known common subunits shared between yeast, Drosophila and the human complexes are shown in GREEN. Cps35 in yeast and Drosophila and its homolog of mammalian Wdr82 shown in BLUE, are found only in Set1A-B/COMPASS. Menin shown in BLUE is found in complex with Trx and the MLL1-2/COMPASS-like complexes. The shared subunits among the trr and the MLL3-4 complexes, Utx, PTIP, PA1 and NCOA6 are shown in PURPLE.