Human Wrnip1 is localized in replication factories in a ubiquitin-binding zinc finger-dependent manner.
Wrnip1 (Werner helicase-interacting protein 1) has been implicated in the bypass of stalled replication forks in bakers' yeast. However, the function(s) of human Wrnip1 has remained elusive so far. Here we report that Wrnip1 is distributed inside heterogeneous structures detectable in nondamaged cells throughout the cell cycle. In an attempt to characterize these structures, we found that Wrnip1 resides in DNA replication factories. Upon treatments that stall replication forks, such as UVC light, the amount of chromatin-bound Wrnip1 and the number of foci significantly increase, further implicating Wrnip1 in DNA replication. Interestingly, the nuclear pattern of Wrnip1 appears to extend to a broader landscape, as it can be detected in promyelocytic leukemia nuclear bodies. The presence of Wrnip1 into these heterogeneous subnuclear structures requires its ubiquitin-binding zinc finger (UBZ) domain, which is able to interact with different ubiquitin (Ub) signals, including mono-Ub and chains linked via lysine 48 and 63. Moreover, the oligomerization of Wrnip1 mediated by its C terminus is also important for proper subnuclear localization. Our study is the first to reveal the composite and regulated topography of Wrnip1 in the human nucleus, highlighting its potential role in replication and other nuclear transactions.
Crosetto
Nicola
N
Institute of Biochemistry II and Cluster of Excellence Macromolecular Complexes, J. W. Goethe University, Theodor-Stern-Kai 7, D-60590 Frankfurt, Main, Germany.
Bienko
Marzena
M
Hibbert
Richard G
RG
Perica
Tina
T
Ambrogio
Chiara
C
Kensche
Tobias
T
Hofmann
Kay
K
Sixma
Titia K
TK
Dikic
Ivan
I
D000074183:ATPases Associated with Diverse Cellular Activities; D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000502:physiology*; D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000737:chemistry; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D008239:Lysine / Q000737:chemistry; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D020349:Surface Plasmon Resonance; D020798:Two-Hybrid System Techniques; D025801:Ubiquitin / Q000737:chemistry*; D016335:Zinc Fingers
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D025801:Ubiquitin; D004247:DNA; C430237:WRNIP1 protein, human; D000074183:ATPases Associated with Diverse Cellular Activities; D008239:Lysine