title: Phosphorylation of a C-terminal auto-inhibitory domain increases SMARCAL1 activity.
abstract: SMARCAL1 promotes the repair and restart of damaged replication forks. Either overexpression or silencing SMARCAL1 causes the accumulation of replication-associated DNA damage. SMARCAL1 is heavily phosphorylated. Here we identify multiple phosphorylation sites, including S889, which is phosphorylated even in undamaged cells. S889 is highly conserved through evolution and it regulates SMARCAL1 activity. Specifically, S889 phosphorylation increases the DNA-stimulated ATPase activity of SMARCAL1 and increases its ability to catalyze replication fork regression. A phosphomimetic S889 mutant is also hyperactive when expressed in cells, while a non-phosphorylatable mutant is less active. S889 lies within a C-terminal region of the SMARCAL1 protein. Deletion of the C-terminal region also creates a hyperactive SMARCAL1 protein suggesting that S889 phosphorylation relieves an auto-inhibitory function of this SMARCAL1 domain. Thus, S889 phosphorylation is one mechanism by which SMARCAL1 activity is regulated to ensure the proper level of fork remodeling needed to maintain genome integrity during DNA synthesis.
authors.affiliation: Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232 USA, Division of Pediatric Hematology/Oncology, Vanderbilt University School of Medicine and Verna and Mars McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA.
authors.forename: Clinton
authors.initials: C
authors.lastname: Carroll
authors.forename: Carol E
authors.initials: CE
authors.lastname: Bansbach
authors.forename: Runxiang
authors.initials: R
authors.lastname: Zhao
authors.forename: Sung Yun
authors.initials: SY
authors.lastname: Jung
authors.forename: Jun
authors.initials: J
authors.lastname: Qin
authors.forename: David
authors.initials: D
authors.lastname: Cortez
mesh_terms: D000595:Amino Acid Sequence; D002460:Cell Line; D004265:DNA Helicases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D017434:Protein Structure, Tertiary
chemical_list: C412482:SMARCAL1 protein, human; D004265:DNA Helicases