• Molecules and Cells
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• v.19 no.2
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• pp.289-293
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• 2005

BAF53 is an actin-related protein that shuttles between nucleus and cytoplasm. In the nucleus, it constitutes an integral component of many chromatin-modifying complexes such as the SWI/SNF, TIP60, TRRAP, and TIP48/49 complexes. BAF53 is essential for growth, but its function remains elusive. BAF53 homologues from yeast to humans have a conserved N-terminal motif, MS_(G/A)(G/A)__(V/L)YGG, which is unique to these proteins. Previously we showed that over-expression of an N-terminal deletion mutant of BAF53 ($BAF53_-{\Delta}N$) reduced the viability of HEK293 and HeLa cells. When we replaced the serine 2 and tyrosine 6 of this N-terminal motif with alanine, over-expression of the alanine-replaced BAF53 strongly impaired the growth of HEK293 cells whereas replacement with aspartate/glutamate had no effect. The alanine-replaced BAF53 mutants also stimulated p53-dependent transcription, in which the SWI/SNF and TRRAP complexes are involved. Our results demonstrate that serine 2 and tyrosine 6 play important roles in BAF53 activity.

• BMB Reports
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• v.55 no.12
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• pp.595-601
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• 2022

Polycomb Repressive Complex 2 (PRC2) exhibits key roles in mammalian development through its temporospatial repression of gene expression. EZH1 or EZH2 is the catalytic subunit of PRC2 that mediates the mono-, di- and tri-methylation of histone H3 lysine 27 (H3K27me1/2/3), H3K27me2/me3 being a hallmark of facultative heterochromatin. PRC2 is a chromatin-modifying enzyme that is recruited to a limited number of "nucleation sites", spreads H3K27 methylation and fosters chromatin compaction. EZH1 and EZH2 exhibit differences in their expression patterns, levels of histone methyltransferase activity (HMT) in the context of PRC2, and DNA/nucleosome binding activity. This suggests that their roles in heterochromatin formation are disparate. Dysregulation of PRC2 activity leads to aberrant gene expression and is implicated in cancer and developmental diseases. In this review, we discuss the distinct function of PRC2/EZH1 and PRC2/EZH2 in the early and late developmental stages. We then discuss the cancers associated with PRC2/EZH1 and PRC2/EZH2.