SMCHD1's ubiquitin-like domain is required for N-terminal dimerization and chromatin localization
Journal Title
Biochemical Journal
Publication Type
epub ahead of print
Abstract
Structural Maintenance of Chromosomes flexible Hinge Domain-containing 1 (SMCHD1) is an epigenetic regulator that mediates gene expression silencing at targeted sites across the genome. Our current understanding of SMCHD1's molecular mechanism, and how substitutions within SMCHD1 lead to the diseases, facioscapulohumeral muscular dystrophy (FSHD) and Bosma arhinia microphthalmia syndrome (BAMS), are only emerging. Recent structural studies of its two component domains - the N-terminal ATPase and C-terminal SMC hinge - suggest that dimerization of each domain plays a central role in SMCHD1 function. Here, using biophysical techniques, we demonstrate that the SMCHD1 ATPase undergoes dimerization in a process that is dependent on both the N-terminal UBL (Ubiquitin-like) domain and ATP binding. We show that neither the dimerization event, nor the presence of a C-terminal extension past the transducer domain, affect SMCHD1's in vitro catalytic activity as the rate of ATP turnover remains comparable to the monomeric protein. We further examined the functional importance of the N-terminal UBL domain in cells, revealing that its targeted deletion disrupts the localization of full-length SMCHD1 to chromatin. These findings implicate UBL-mediated SMCHD1 dimerization as a crucial step for chromatin interaction, and thereby for promoting SMCHD1-mediated gene silencing.
Publisher
Portland Press
Keywords
GHKL ATPase; SMC proteins; UBL domain; nucleic acid binding proteins; protein-protein interactions
WEHI Research Division(s)
Epigenetics And Development; Inflammation
PubMed ID
34109974
Open Access at Publisher's Site
https://doi.org/10.1042/BCJ20210278
Rights Notice
Refer to copyright notice on published article.


Creation Date: 2021-06-21 10:25:58
Last Modified: 2021-06-21 10:42:59
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