TY  - JOUR
A1  - Kaiser, Sebastian
A1  - Sauer, Florian
A1  - Kisker, Caroline
T1  - The structural and functional characterization of human RecQ4 reveals insights into its helicase mechanism
JF  - Nature Communications
N2  - RecQ4 is a member of the RecQ helicase family, an evolutionarily conserved class of enzymes, dedicated to preserving genomic integrity by operating in telomere maintenance, DNA repair and replication. While reduced RecQ4 activity is associated with cancer predisposition and premature aging, RecQ4 upregulation is related to carcinogenesis and metastasis. Within the RecQ family, RecQ4 assumes an exceptional position, lacking several characteristic RecQ domains. Here we present the crystal structure of human RecQ4, encompassing the conserved ATPase core and a novel C-terminal domain that lacks resemblance to the RQC domain observed in other RecQ helicases. The new domain features a zinc-binding site and two distinct types of winged-helix domains, which are not involved in canonical DNA binding or helicase activity. Based on our structural and functional analysis, we propose that RecQ4 exerts a helicase mechanism, which may be more closely related to bacterial RecQ helicases than to its human family members.
KW  - x-ray crystallography
KW  - enzymes
KW  - RecQ4
KW  - humans
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170769
VL  - 8
IS  - 15907
ER  - 
TY  - JOUR
A1  - Peissert, Stefan
A1  - Sauer, Florian
A1  - Grabarczyk, Daniel B.
A1  - Braun, Cathy
A1  - Sander, Gudrun
A1  - Poterszman, Arnaud
A1  - Egly, Jean-Marc
A1  - Kuper, Jochen
A1  - Kisker, Caroline
T1  - In TFIIH the Arch domain of XPD is mechanistically essential for transcription and DNA repair
JF  - Nature Communications
N2  - The XPD helicase is a central component of the general transcription factor TFIIH which plays major roles in transcription and nucleotide excision repair (NER). Here we present the high-resolution crystal structure of the Arch domain of XPD with its interaction partner MAT1, a central component of the CDK activating kinase complex. The analysis of the interface led to the identification of amino acid residues that are crucial for the MAT1-XPD interaction. More importantly, mutagenesis of the Arch domain revealed that these residues are essential for the regulation of (i) NER activity by either impairing XPD helicase activity or the interaction of XPD with XPG; (ii) the phosphorylation of the RNA polymerase II and RNA synthesis. Our results reveal how MAT1 shields these functionally important residues thereby providing insights into how XPD is regulated by MAT1 and defining the Arch domain as a major mechanistic player within the XPD scaffold.
KW  - nucleotide excision repair
KW  - nuclear receptors
KW  - helicase
KW  - transactivation
KW  - fluorescence
KW  - recognition
KW  - subunit
KW  - binding
KW  - sulfur
KW  - kinease
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-229857
VL  - 11
IS  - 1
ER  - 
TY  - JOUR
A1  - Fischer, Annette
A1  - Harrison, Kelly S
A1  - Ramirez, Yesid
A1  - Auer, Daniela
A1  - Chowdhury, Suvagata Roy
A1  - Prusty, Bhupesh K
A1  - Sauer, Florian
A1  - Dimond, Zoe
A1  - Kisker, Caroline
A1  - Hefty, P Scott
A1  - Rudel, Thomas
T1  - Chlamydia trachomatis-containing vacuole serves as deubiquitination platform to stabilize Mcl-1 and to interfere with host defense
JF  - eLife
N2  - Obligate intracellular Chlamydia trachomatis replicate in a membrane-bound vacuole called inclusion, which serves as a signaling interface with the host cell. Here, we show that the chlamydial deubiquitinating enzyme (Cdu) 1 localizes in the inclusion membrane and faces the cytosol with the active deubiquitinating enzyme domain. The structure of this domain revealed high similarity to mammalian deubiquitinases with a unique α-helix close to the substrate-binding pocket. We identified the apoptosis regulator Mcl-1 as a target that interacts with Cdu1 and is stabilized by deubiquitination at the chlamydial inclusion. A chlamydial transposon insertion mutant in the Cdu1-encoding gene exhibited increased Mcl-1 and inclusion ubiquitination and reduced Mcl-1 stabilization. Additionally, inactivation of Cdu1 led to increased sensitivity of C. trachomatis for IFNγ and impaired infection in mice. Thus, the chlamydial inclusion serves as an enriched site for a deubiquitinating activity exerting a function in selective stabilization of host proteins and protection from host defense.
KW  - cell-autonomous defense
KW  - Chlamydia trachomatis
KW  - deubiquitinase
KW  - Mcl-1
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-171073
VL  - 6
IS  - e21465
ER  -