Why are ATP-driven microtubule minus-end directed motors critical to plants? An overview of plant multifunctional kinesins

2020 ◽  
Vol 47 (6) ◽  
pp. 524 ◽  
Author(s):  
Iftikhar Ali ◽  
Wei-Cai Yang
Keyword(s):  
Chromosome Segregation ◽  
Cytoplasmic Streaming ◽  
Atp Hydrolysis ◽  
Biotic And Abiotic Stress ◽  
Functional Interaction ◽  
Variable Regions ◽  
Cell Structures ◽  
Variable Domains ◽  
Division Cell ◽  
Hormonal Signalling

In plants, microtubule and actin cytoskeletons are involved in key processes including cell division, cell expansion, growth and development, biotic and abiotic stress, tropisms, hormonal signalling as well as cytoplasmic streaming in growing pollen tubes. Kinesin enzymes have a highly conserved motor domain for binding microtubule cytoskeleton assisting these motors to organise their own tracks, the microtubules by using chemical energy of ATP hydrolysis. In addition to this conserved binding site, kinesins possess non-conserved variable domains mediating structural and functional interaction of microtubules with other cell structures to perform various cellular jobs such as chromosome segregation, spindle formation and elongation, transport of organelles as well as microtubules-actins cross linking and microtubules sliding. Therefore, how the non-motor variable regions specify the kinesin function is of fundamental importance for all eukaryotic cells. Kinesins are classified into ~17 known families and some ungrouped orphans, of which ~13 families have been recognised in plants. Kinesin-14 family consisted of plant specific microtubules minus end-directed motors, are much diverse and unique to plants in the sense that they substitute the functions of animal dynein. In this review, we explore the functions of plant kinesins, especially from non-motor domains viewpoint, focussing mainly on recent work on the origin and functional diversity of motors that drive microtubule minus-end trafficking events.

scholarly journals Meiosis-specific recombinase Dmc1 is a potent inhibitor of the Srs2 antirecombinase

2018 ◽  
Vol 115 (43) ◽  
pp. E10041-E10048 ◽  
Author(s):  
J. Brooks Crickard ◽  
Kyle Kaniecki ◽  
Youngho Kwon ◽  
Patrick Sung ◽  
Eric C. Greene
Keyword(s):  
Chromosome Segregation ◽  
Single Molecule ◽  
Atp Hydrolysis ◽  
Potent Inhibitor ◽  
Chromosomal Rearrangements ◽  
Motor Protein ◽  
Product Formation ◽  
Gross Chromosomal Rearrangements ◽  
Strand Annealing ◽  
Hydrolysis Activity

Cross-over recombination products are a hallmark of meiosis because they are necessary for accurate chromosome segregation and they also allow for increased genetic diversity during sexual reproduction. However, cross-overs can also cause gross chromosomal rearrangements and are therefore normally down-regulated during mitotic growth. The mechanisms that enhance cross-over product formation upon entry into meiosis remain poorly understood. In Saccharomyces cerevisiae, the Superfamily 1 (Sf1) helicase Srs2, which is an ATP hydrolysis-dependent motor protein that actively dismantles recombination intermediates, promotes synthesis-dependent strand annealing, the result of which is a reduction in cross-over recombination products. Here, we show that the meiosis-specific recombinase Dmc1 is a potent inhibitor of Srs2. Biochemical and single-molecule assays demonstrate that Dmc1 acts by inhibiting Srs2 ATP hydrolysis activity, which prevents the motor protein from undergoing ATP hydrolysis-dependent translocation on Dmc1-bound recombination intermediates. We propose a model in which Dmc1 helps contribute to cross-over formation during meiosis by antagonizing the antirecombinase activity of Srs2.

Enterococcus faecalis divIVA: an essential gene involved in cell division, cell growth and chromosome segregation

Microbiology ◽  
2005 ◽  
Vol 151 (5) ◽  
pp. 1381-1393 ◽  
Author(s):  
Sandra Ramirez-Arcos ◽  
Mingmin Liao ◽  
Susan Marthaler ◽  
Marc Rigden ◽  
Jo-Anne R. Dillon
Keyword(s):  
Cell Division ◽  
Enterococcus Faecalis ◽  
Chromosome Segregation ◽  
Essential Gene ◽  
Phylogenetic Distance ◽  
Multifunctional Protein ◽  
E Coli ◽  
Insertional Inactivation ◽  
Species Specific ◽  
Division Cell

Enterococcus faecalis divIVA (divIVA Ef) is an essential gene implicated in cell division and chromosome segregation. This gene was disrupted by insertional inactivation creating E. faecalis JHSR1, which was viable only when a wild-type copy of divIVA Ef was expressed in trans, confirming the essentiality of the gene. The absence of DivIVAEf in E. faecalis JHSR1 inhibited proper cell division, which resulted in abnormal cell clusters possessing enlarged cells of altered shape instead of the characteristic diplococcal morphology of enterococci. The lower viability of the divIVA Ef mutant is caused by improper nucleoid segregation and impaired septation within the numerous cells generated in each cluster. Overexpression of DivIVAEf in Escherichia coli KJB24 resulted in enlarged cells with disrupted cell division, suggesting that this round E. coli mutant strain could be used as an indicator for functionality of DivIVAEf. A Bacillus subtilis divIVA mutant was not complemented by DivIVAEf, indicating that this protein does not recognize DivIVA-specific target sites in B. subtilis, or that it does not interact with other proteins of the cell division machinery of this micro-organism. DivIVAEf also failed to complement a Streptococcus pneumoniae divIVA mutant, supporting the phylogenetic distance between Enterococcus and Streptococcus. Our results indicate that DivIVA is a species-specific multifunctional protein implicated in cell division and chromosome segregation in E. faecalis.

scholarly journals Topological in vitro loading of the budding yeast cohesin ring onto DNA

2018 ◽  
Vol 1 (5) ◽  
pp. e201800143 ◽  
Author(s):  
Masashi Minamino ◽  
Torahiko L Higashi ◽  
Céline Bouchoux ◽  
Frank Uhlmann
Keyword(s):  
Chromosome Segregation ◽  
Genome Organization ◽  
Atp Hydrolysis ◽  
Budding Yeast ◽  
Reaction Step ◽  
Subsequent Reaction ◽  
Transition State Analog ◽  
Sister Chromatids

The ring-shaped chromosomal cohesin complex holds sister chromatids together by topological embrace, a prerequisite for accurate chromosome segregation. Cohesin plays additional roles in genome organization, transcriptional regulation, and DNA repair. The cohesin ring includes an ABC family ATPase, but the molecular mechanism by which the ATPase contributes to cohesin function is not yet understood. In this study, we have purified budding yeast cohesin, as well as its Scc2–Scc4 cohesin loader complex, and biochemically reconstituted ATP-dependent topological cohesin loading onto DNA. Our results reproduce previous observations obtained using fission yeast cohesin, thereby establishing conserved aspects of cohesin behavior. Unexpectedly, we find that nonhydrolyzable ATP ground state mimetics ADP·BeF2, ADP·BeF3−, and ADP·AlFx, but not a hydrolysis transition state analog ADP·VO43−, support cohesin loading. The energy from nucleotide binding is sufficient to drive the DNA entry reaction into the cohesin ring. ATP hydrolysis, believed to be essential for in vivo cohesin loading, must serve a subsequent reaction step. These results provide molecular insights into cohesin function and open new experimental opportunities that the budding yeast model affords.

scholarly journals RNase H-dependent PCR enables highly specific amplification of antibody variable domains from single B-cells

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0241803
Author(s):  
John Crissman ◽  
Yuhao Lin ◽  
Kevin Separa ◽  
Madeleine Duquette ◽  
Michael Cohen ◽  
...  
Keyword(s):  
B Cells ◽  
Recombinant Antibody ◽  
Pcr Primers ◽  
Rnase H ◽  
Sequence Information ◽  
Homogeneous Sample ◽  
Variable Regions ◽  
Large Numbers ◽  
Variable Domains ◽  
Antibody Discovery

Immunization-based antibody discovery platforms require robust and effective protocols for the amplification, cloning, expression, and screening of antibodies from large numbers of B-cells in order to effectively capture the diversity of an experienced Ig-repertoire. Multiplex PCR using a series of forward and reverse primers designed to recover antibodies from a range of different germline sequences is challenging because primer design requires the recovery of full length antibody sequences, low starting template concentrations, and the need for all the primers to function under the same PCR conditions. Here we demonstrate several advantages to incorporating RNase H2-dependent PCR (rh-PCR) into a high-throughput, antibody-discovery platform. Firstly, rh-PCR eliminated primer dimer synthesis to below detectable levels, thereby eliminating clones with a false positive antibody titer. Secondly, by increasing the specificity of PCR, the rh-PCR primers increased the recovery of cognate antibody variable regions from single B-cells, as well as downstream recombinant antibody titers. Finally, we demonstrate that rh-PCR primers provide a more homogeneous sample pool and greater sequence quality in a Next Generation Sequencing-based approach to obtaining DNA sequence information from large numbers of cloned antibody cognate pairs. Furthermore, the higher specificity of the rh-PCR primers allowed for a better match between native antibody germline sequences and the VL/VH fragments amplified from single B-cells.

scholarly journals Recombination and chromosome segregation

2004 ◽  
Vol 359 (1441) ◽  
pp. 61-69 ◽  
Author(s):  
David J. Sherratt ◽  
Britta Søballe ◽  
François–Xavier Barre ◽  
Sergio Filipe ◽  
Ivy Lau ◽  
...  
Keyword(s):  
Cell Division ◽  
Homologous Recombination ◽  
Chromosome Segregation ◽  
Atp Hydrolysis ◽  
Daughter Cells ◽  
Recombination Proteins ◽  
Recombination System ◽  
Associated Proteins ◽  
Stalled Replication Forks ◽  
Circular Chromosomes

The duplication of DNA and faithful segregation of newly replicated chromosomes at cell division is frequently dependent on recombinational processes. The rebuilding of broken or stalled replication forks is universally dependent on homologous recombination proteins. In bacteria with circular chromosomes, crossing over by homologous recombination can generate dimeric chromosomes, which cannot be segregated to daughter cells unless they are converted to monomers before cell division by the conserved Xer site–specific recombination system. Dimer resolution also requires FtsK, a division septum–located protein, which coordinates chromosome segregation with cell division, and uses the energy of ATP hydrolysis to activate the dimer resolution reaction. FtsK can also translocate DNA, facilitate synapsis of sister chromosomes and minimize entanglement and catenation of newly replicated sister chromosomes. The visualization of the replication/recombination–associated proteins, RecQ and RarA, and specific genes within living Escherichia coli cells, reveals further aspects of the processes that link replication with recombination, chromosome segregation and cell division, and provides new insight into how these may be coordinated.

scholarly journals MukB ATPases are regulated independently by the N- and C-terminal domains of MukF kleisin

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Katarzyna Zawadzka ◽  
Pawel Zawadzki ◽  
Rachel Baker ◽  
Karthik V Rajasekar ◽  
Florence Wagner ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Chromosome Segregation ◽  
Atp Hydrolysis ◽  
Helix Bundle ◽  
Terminal Domain ◽  
Terminal Domains

The Escherichia coli SMC complex, MukBEF, acts in chromosome segregation. MukBEF shares the distinctive architecture of other SMC complexes, with one prominent difference; unlike other kleisins, MukF forms dimers through its N-terminal domain. We show that a 4-helix bundle adjacent to the MukF dimerisation domain interacts functionally with the MukB coiled-coiled ‘neck’ adjacent to the ATPase head. We propose that this interaction leads to an asymmetric tripartite complex, as in other SMC complexes. Since MukF dimerisation is preserved during this interaction, MukF directs the formation of dimer of dimer MukBEF complexes, observed previously in vivo. The MukF N- and C-terminal domains stimulate MukB ATPase independently and additively. We demonstrate that impairment of the MukF interaction with MukB in vivo leads to ATP hydrolysis-dependent release of MukBEF complexes from chromosomes.

scholarly journals Mutation of the ATP-Binding Pocket of SSA1 Indicates That a Functional Interaction Between Ssa1p and Ydj1p Is Required for Post-translational Translocation Into the Yeast Endoplasmic Reticulum

Genetics ◽  
2000 ◽  
Vol 156 (2) ◽  
pp. 501-512 ◽  
Author(s):  
Amie J McClellan ◽  
Jeffrey L Brodsky
Keyword(s):  
Atpase Activity ◽  
Atp Hydrolysis ◽  
Protein Translocation ◽  
Binding Pocket ◽  
Atp Binding ◽  
Dominant Effect ◽  
Functional Interaction ◽  
Mutant Proteins

Abstract The translocation of proteins across the yeast ER membrane requires ATP hydrolysis and the action of DnaK (hsp70) and DnaJ homologues. In Saccharomyces cerevisiae the cytosolic hsp70s that promote post-translational translocation are the products of the Ssa gene family. Ssa1p maintains secretory precursors in a translocation-competent state and interacts with Ydj1p, a DnaJ homologue. Although it has been proposed that Ydj1p stimulates the ATPase activity of Ssa1p to release preproteins and engineer translocation, support for this model is incomplete. To this end, mutations in the ATP-binding pocket of SSA1 were constructed and examined both in vivo and in vitro. Expression of the mutant Ssa1p's slows wild-type cell growth, is insufficient to support life in the absence of functional Ssa1p, and results in a dominant effect on post-translational translocation. The ATPase activity of the purified mutant proteins was not enhanced by Ydj1p and the mutant proteins could not bind an unfolded polypeptide substrate. Our data suggest that a productive interaction between Ssa1p and Ydj1p is required to promote protein translocation.

scholarly journals Smc5/6, an atypical SMC complex with two RING-type subunits

2020 ◽  
Vol 48 (5) ◽  
pp. 2159-2171 ◽  
Author(s):  
Roger Solé-Soler ◽  
Jordi Torres-Rosell
Keyword(s):  
Chromosome Segregation ◽  
Atp Hydrolysis ◽  
Ring Domain ◽  
E3 Ligases ◽  
Ring Type ◽  
Sister Chromatids ◽  
Ubiquitin Ligase Activity ◽  
Sumo Ligase ◽  
Associated Proteins ◽  
Structural Maintenance Of Chromosomes

The Smc5/6 complex plays essential roles in chromosome segregation and repair, by promoting disjunction of sister chromatids. The core of the complex is constituted by an heterodimer of Structural Maintenance of Chromosomes (SMC) proteins that use ATP hydrolysis to dynamically associate with and organize chromosomes. In addition, the Smc5/6 complex contains six non-SMC subunits. Remarkably, and differently to other SMC complexes, the Nse1 and Nse2 subunits contain RING-type domains typically found in E3 ligases, pointing to the capacity to regulate other proteins and complexes through ubiquitin-like modifiers. Nse2 codes for a C-terminal SP-RING domain with SUMO ligase activity, assisting Smc5/6 functions in chromosome segregation through sumoylation of several chromosome-associated proteins. Nse1 codes for a C-terminal NH-RING domain and, although it has been proposed to have ubiquitin ligase activity, no Smc5/6-dependent ubiquitylation target has been described to date. Here, we review the function of the two RING domains of the Smc5/6 complex in the broader context of SMC complexes as global chromosome organizers of the genome.

scholarly journals ¡vIVA la DivIVA!

2019 ◽  
Vol 201 (21) ◽  
Author(s):  
Lauren R. Hammond ◽  
Maria L. White ◽  
Prahathees J. Eswara
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Parental Cell ◽  
Model Organisms ◽  
Posttranslational Regulation ◽  
Bacterial Cell Division ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Division Cell

ABSTRACT Reproduction in the bacterial kingdom predominantly occurs through binary fission—a process in which one parental cell is divided into two similarly sized daughter cells. How cell division, in conjunction with cell elongation and chromosome segregation, is orchestrated by a multitude of proteins has been an active area of research spanning the past few decades. Together, the monumental endeavors of multiple laboratories have identified several cell division and cell shape regulators as well as their underlying regulatory mechanisms in rod-shaped Escherichia coli and Bacillus subtilis, which serve as model organisms for Gram-negative and Gram-positive bacteria, respectively. Yet our understanding of bacterial cell division and morphology regulation is far from complete, especially in noncanonical and non-rod-shaped organisms. In this review, we focus on two proteins that are highly conserved in Gram-positive organisms, DivIVA and its homolog GpsB, and attempt to summarize the recent advances in this area of research and discuss their various roles in cell division, cell growth, and chromosome segregation in addition to their interactome and posttranslational regulation.

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