Reconstitution and subunit geometry of human condensin complexes

Onn, Itay; Aono, Nobuki; Hirano, Mako; Hirano, Takeshi

doi:10.1038/sj.emboj.7601562

Cited by 89 publications

(120 citation statements)

References 38 publications

(75 reference statements)

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“…Silver stain analysis revealed that SMC2-SMC4 heterodimer formation was not affected by any of the mutations, and immunoblotting with CAP-D2 and CAP-H antibodies indicated that the non-SMC subunits of condensin I assembled normally with all of the various mutants. This agrees with in vitro data using baculovirus expressed condensin I (Onn et al, 2007). Thus, a functional condensin ATPase is not a prerequisite for assembly of the complex in vivo.…”

Section: Smc2 Atpase Activity Is Not Required For Formation Of the Cosupporting

confidence: 81%

“…Our in vivo studies of condensin function are consistent with recent in vitro studies from the Hirano laboratory, which showed that purified SMC2 undergoes a conformational shift in the presence of ATP, leading to the suggestion that ATP binding might open the hinge region (Onn et al, 2007). Recent studies of cohesin have shown that loading of the complex onto chromatin is caused by transient opening of the hinge domain, and it was hypothesized that this conformational change could be the result of either ATP binding or hydrolysis (Gruber et al, 2006).…”

Section: Mechanistic Differences Between Cohesin and Condensin Atpasesupporting

confidence: 77%

“…A separate study using baculovirus purified condensin I also found that ATPase mutations in either SMC2 or SMC4 failed to affect the formation of the holocomplex in vitro (Onn et al, 2007). In contrast, ATP binding in the cohesin subunit SMC1 but not SMC3 is essential for interactions with Scc1 and therefore for assembly of the cohesin complex (Arumugam et al, 2003;Weitzer et al, 2003).…”

Section: Mechanistic Differences Between Cohesin and Condensin Atpasementioning

confidence: 97%

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Molecular and Genetic Analysis of Condensin Function in Vertebrate Cells

Hudson

Ohta

Freisinger

et al. 2008

MBoC

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We engineered mutants into residues of SMC2 to dissect the role of ATPase function in the condensin complex. These residues are predicted to be involved in ATP binding or hydrolysis and in the Q-loop, which is thought to act as a mediator of conformational changes induced by substrate binding. All the engineered ATPase mutations resulted in lethality when introduced into SMC2 null cells. We found that ATP binding, but not hydrolysis, is essential to allow stable condensin association with chromosomes. How SMC proteins bind and interact with DNA is still a major question. Cohesin may form a ring structure that topologically encircles DNA. We examined whether condensin behaves in an analogous way to its cohesin counterpart, and we have generated a cleavable form of biologically active condensin with PreScission protease sites engineered into the SMC2 protein. This has allowed us to demonstrate that topological integrity of the SMC2-SMC4 heterodimer is not necessary for the stability of the condensin complex in vitro or for its stable association with mitotic chromosomes. Thus, despite their similar molecular organization, condensin and cohesin exhibit fundamental differences in their structure and function.

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Section: Smc2 Atpase Activity Is Not Required For Formation Of the Cosupporting

confidence: 81%

Section: Mechanistic Differences Between Cohesin and Condensin Atpasesupporting

confidence: 77%

Section: Mechanistic Differences Between Cohesin and Condensin Atpasementioning

confidence: 97%

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Molecular and Genetic Analysis of Condensin Function in Vertebrate Cells

Hudson

Ohta

Freisinger

et al. 2008

MBoC

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“…Electron microscopic analyses have visualized the highly characteristic architecture of condensin I (Anderson et al 2002), and protein-protein interaction assays using recombinant subunits have revealed the geometry of the subunits within each complex ( Fig. 1A; Onn et al 2007). …”

Section: Eukaryotamentioning

confidence: 99%

Condensins: universal organizers of chromosomes with diverse functions

2012

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Condensins are multisubunit protein complexes that play a fundamental role in the structural and functional organization of chromosomes in the three domains of life. Most eukaryotic species have two different types of condensin complexes, known as condensins I and II, that fulfill nonoverlapping functions and are subjected to differential regulation during mitosis and meiosis. Recent studies revealed that the two complexes contribute to a wide variety of interphase chromosome functions, such as gene regulation, recombination, and repair. Also emerging are their cell type- and tissue-specific functions and relevance to human disease. Biochemical and structural analyses of eukaryotic and bacterial condensins steadily uncover the mechanisms of action of this class of highly sophisticated molecular machines. Future studies on condensins will not only enhance our understanding of chromosome architecture and dynamics, but also help address a previously underappreciated yet profound set of questions in chromosome biology.

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“…Potential for elastic behavior of HEAT-repeat molecules is suggested by (i) their solenoidal shapes evocative of a Slinky-like "spring" (14)(15)(16)(17)(18)(19), and (ii) their involvement in reactions involving DNA and membranes, both readily deformable and thus susceptible to an elastic protein/substrate response, e.g., Ataxia telangiectasia and Rad3 related and TOR (15), and cohesin and condensin (e.g., [20][21][22]. Further, TOR responds to plasma membrane deformations (e.g., 23); and the HEAT-repeat protein PR65 is the scaffolding subunit for PP2A, which is directly implicated in responses to spindle tension [e.g., (8); see below].…”

mentioning

confidence: 99%

PR65, the HEAT-repeat scaffold of phosphatase PP2A, is an elastic connector that links force and catalysis

Grinthal¹,

Adamovic

Weiner³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

117

114

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PR65 is the two-layered (α-α solenoid) HEAT-repeat (Huntingtin, elongation factor 3, a subunit of protein phosphatase 2A, PI3 kinase target of rapamycin 1) scaffold of protein phosphatase PP2A. Molecular dynamics simulations predict that, at forces expected in living systems, PR65 undergoes (visco-)elastic deformations in response to pulling/pushing on its ends. At lower forces, smooth global flexural and torsional changes occur via even redistribution of stress along the hydrophobic core of the molecule. At intermediate forces, helix-helix separation along one layer ("fracturing") leads to global relaxation plus loss of contact in the other layer to unstack the affected units. Fracture sites are determined by unusual sequences in contiguous interhelix turns. Normal mode analysis of the heterotrimeric PP2A enzyme reveals that its ambient conformational fluctuations are dominated by elastic deformations of PR65, which introduce a mechanical linkage between the separately bound regulatory and catalytic subunits. PR65-dominated fluctuations of PP2A have the effect of opening and closing the enzyme's substrate binding/catalysis interface, as well as altering the positions of certain catalytic residues. These results suggest that substrate binding/catalysis are sensitive to mechanical force. Force could be imposed from the outside (e.g., in PP2A's response to spindle tension) or arise spontaneously (e.g., in PP2A's interaction with unstructured proteins such as Tau, a microtubule-associated Alzheimer's-implicated protein). The presented example supports the view that conformation and function of protein complexes can be modulated by mechanical energy inputs, as well as by chemical energy inputs from ligand binding. Given that helical-repeat proteins are involved in many cellular processes, the findings also encourage the view that mechanical forces may be of widespread importance.helical-repeat protein | protein elasticity | protein mechanotransduction | spindle tension

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Reconstitution and subunit geometry of human condensin complexes

Cited by 89 publications

References 38 publications

Molecular and Genetic Analysis of Condensin Function in Vertebrate Cells

Molecular and Genetic Analysis of Condensin Function in Vertebrate Cells

Condensins: universal organizers of chromosomes with diverse functions

PR65, the HEAT-repeat scaffold of phosphatase PP2A, is an elastic connector that links force and catalysis

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