Structural Biology of Replication Initiation Factor Mcm10

Abstract

Minichromosome maintenance protein 10 (Mcm10) is a non-enzymatic replication factor required for proper assembly of the eukaryotic replication fork. Mcm10 interacts with single-stranded and double-stranded DNA, polymerase α, and Mcm2-7, and is important for activation of the pre-replicative complex and recruitment of subsequent proteins to the origin at the onset of S-phase. In addition, Mcm10 has recently been implicated in coordination of helicase and polymerase activities during replication fork progression. The nature of Mcm10's involvement in these activities, whether direct or indirect, remains unknown. However, recent biochemical and structural characterization of Mcm10 from multiple organisms has provided insights into how Mcm10 utilizes a modular architecture to act as a replisome scaffold, which helps to define possible roles in origin DNA melting, pol α recruitment and coordination of enzymatic activities during elongation.

Cell-Cycle-Regulated Interaction between Mcm10 and Double Hexameric Mcm2-7 Is Required for Helicase Splitting and Activation during S Phase

“…Previous studies have focused on the highly conserved internal domain, which is composed of an OB-fold which mediates interaction with pol α and PCNA, and a zinc finger responsible for DNA binding (Figure 3B) (Du et al, 2012; Thu and Bielinsky, 2014). Through truncation of Mcm10 protein, we first deduce that the Mcm10 internal domain also binds Mcm2 (Figure 3C, compare lanes 5 and 6).…”

“…Due to robust and irreversible binding between GFP and GBP, stable heterodimerization between Mcm10 and Mcm2 or Mcm4 might have been expected to interfere with Mcm10 interaction with other proteins (e.g. pol α, Orc2/5, Dpb11, Cdc45 and PCNA) (Du et al, 2012; Thu and Bielinsky, 2014). However, stable fusion between Mcm10 and Mcm2 or Mcm4 does not pose a detectable threat to growth in WT cells.…”

MCM10: One tool for all—Integrity, maintenance and damage control

“…The core of Mcm10 harbors the evolutionarily conserved and essential internal domain (ID), which is required for DNA and protein binding [5–7]. The ID is flanked by an N-terminal domain (NTD), which displays a coiled coil (CC) motif of considerable sequence similarity among species [7, 8].…”

“…The ID is flanked by an N-terminal domain (NTD), which displays a coiled coil (CC) motif of considerable sequence similarity among species [7, 8]. In contrast, the C-terminal domain (CTD) varies highly from uni- to multicellular organisms and is distinguished by a large metazoan-specific extension [9].…”

Mcm10 Self-Association Is Mediated by an N-Terminal Coiled-Coil Domain

“…An N-terminal coiled-coil (CC) domain (NTD) has been implicated in Mcm10 self-association [20] and the interaction with Mec3, a subunit of the 9-1-1 clamp (Alver and Bielinsky, unpublished results). In addition, the protein has a highly conserved internal (ID) and vertebrate-specific C-terminal domain (CTD) that bind DNA and the catalytic (p180) subunit of pol α [20], [34], [37]. The yeast orthologs have also been shown to interact with DNA and pol α despite the apparent lack of the CTD [16], [19], [21], [38].…”