Histone-lysine N-methyltransferase SETD1B (SET domain-containing protein 1B, hSET1B, lysine N-methyltransferase 2G, SETD1B, KIAA1076, KMT2G, SET1B)

Function

• histone methyltransferase that specifically methylates Lys-4 of histone H3, when part of the SET1 histone methyltransferase (HMT) complex, but not if the neighboring Lys-9 is already methylated
• histone H3 Lys-4 methylation represents a specific tag for epigenetic transcriptional activation
• non-overalpping localization with SETD1A suggests that SETD1A & SETD1B make non-redundant contributions to the epigenetic control of chromatin structure & gene expression
• specifically tri-methylates Lys-4 of histone H3 in vitro
• interacts with HCFC1
• component of the SET1 complex

S-adenosyl-L-methionine + histone L-lysine <--> S-adenosyl-L-homocysteine + histone N(6)-methyl-L-lysine

Structure

• contains 1 post-SET domain
• contains 1 RRM (RNA recognition motif) domain
• contains 1 SET domain

Compartment

• nuclear speckle
• localizes to a largely non-overlapping set of euchromatic nuclear speckles with SETD1A, suggesting that SETD1A & SET1B each bind to a unique set of target genes

More general terms

• histone N-methyltransferase
• SET domain-containing protein
• phosphoprotein

Component of

• Set1/Ash2 histone methyltransferase (HMT) complex

Database

• UniProt: http://www.uniprot.org/uniprot/Q9UPS6.html