5hoi

From Proteopedia

(Difference between revisions)
Jump to: navigation, search
Line 11: Line 11:
<div style="background-color:#fffaf0;">
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
== Publication Abstract from PubMed ==
-
Efficient duplication of the genome requires the concerted action of helicase and DNA polymerases at replication forks to avoid stalling of the replication machinery and consequent genomic instability. In eukaryotes, the physical coupling between helicase and DNA polymerases remains poorly understood. Here we define the molecular mechanism by which the yeast Ctf4 protein links the Cdc45-MCM-GINS (CMG) DNA helicase to DNA polymerase alpha (Pol alpha) within the replisome. We use X-ray crystallography and electron microscopy to show that Ctf4 self-associates in a constitutive disk-shaped trimer. Trimerization depends on a beta-propeller domain in the carboxy-terminal half of the protein, which is fused to a helical extension that protrudes from one face of the trimeric disk. Critically, Pol alpha and the CMG helicase share a common mechanism of interaction with Ctf4. We show that the amino-terminal tails of the catalytic subunit of Pol alpha and the Sld5 subunit of GINS contain a conserved Ctf4-binding motif that docks onto the exposed helical extension of a Ctf4 protomer within the trimer. Accordingly, we demonstrate that one Ctf4 trimer can support binding of up to three partner proteins, including the simultaneous association with both Pol alpha and GINS. Our findings indicate that Ctf4 can couple two molecules of Pol alpha to one CMG helicase within the replisome, providing a new model for lagging-strand synthesis in eukaryotes that resembles the emerging model for the simpler replisome of Escherichia coli. The ability of Ctf4 to act as a platform for multivalent interactions illustrates a mechanism for the concurrent recruitment of factors that act together at the fork.
+
Replisome assembly at eukaryotic replication forks connects the DNA helicase to DNA polymerases and many other factors. The helicase binds the leading-strand polymerase directly, but is connected to the Pol alpha lagging-strand polymerase by the trimeric adaptor Ctf4. Here, we identify new Ctf4 partners in addition to Pol alpha and helicase, all of which contain a "Ctf4-interacting-peptide" or CIP-box. Crystallographic analysis classifies CIP-boxes into two related groups that target different sites on Ctf4. Mutations in the CIP-box motifs of the Dna2 nuclease or the rDNA-associated protein Tof2 do not perturb DNA synthesis genome-wide, but instead lead to a dramatic shortening of chromosome 12 that contains the large array of rDNA repeats. Our data reveal unexpected complexity of Ctf4 function, as a hub that connects multiple accessory factors to the replisome. Most strikingly, Ctf4-dependent recruitment of CIP-box proteins couples other processes to DNA synthesis, including rDNA copy-number regulation.
-
A Ctf4 trimer couples the CMG helicase to DNA polymerase alpha in the eukaryotic replisome.,Simon AC, Zhou JC, Perera RL, van Deursen F, Evrin C, Ivanova ME, Kilkenny ML, Renault L, Kjaer S, Matak-Vinkovic D, Labib K, Costa A, Pellegrini L Nature. 2014 May 4. doi: 10.1038/nature13234. PMID:24805245<ref>PMID:24805245</ref>
+
Ctf4 Is a Hub in the Eukaryotic Replisome that Links Multiple CIP-Box Proteins to the CMG Helicase.,Villa F, Simon AC, Ortiz Bazan MA, Kilkenny ML, Wirthensohn D, Wightman M, Matak-Vinkovic D, Pellegrini L, Labib K Mol Cell. 2016 Jul 5. pii: S1097-2765(16)30240-4. doi:, 10.1016/j.molcel.2016.06.009. PMID:27397685<ref>PMID:27397685</ref>
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

Revision as of 06:30, 26 July 2016

Crystal structure of the carboxy-terminal domain of yeast Ctf4 bound to Tof2.

5hoi, resolution 3.30Å

Drag the structure with the mouse to rotate

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/5hoi"
Personal tools