Abstract:
:Bidirectional cargo transport by molecular motors in cells is a complex phenomenon in which the cargo (usually a vesicle) alternately moves in retrograde and anterograde directions. In this case, teams of oppositely pulling motors (e.g., kinesin and dynein) bind to the cargo, simultaneously, and 'coordinate' their activity such that the motion consists of spells of positively and negatively directed segments, separated by pauses of varying duration. A set of recent experiments have analyzed the bidirectional motion of endosomes in the amoeba D. discoideum in detail. It was found that in between directional switches, a team of five to six dyneins stall a cargo against a stronger kinesin in a tug of war, which lasts for almost a second. As the mean detachment time of a kinesin under its stall load was also observed to be ∼1 s, we infer that the collective detachment time of the dynein assembly must also be similar. Here, we analyze this inference from a modeling perspective, using experimentally measured single-molecule parameters as inputs. We find that the commonly assumed exponential load-dependent detachment rate is inconsistent with observations, as it predicts that a five-dynein assembly will detach under its combined stall load in less than a hundredth of a second. A modified model where the load-dependent unbinding rate is assumed to saturate at stall-force level for super-stall loads gives results which are in agreement with experimental data. Our analysis suggests that the load-dependent detachment of a dynein in a team is qualitatively different at sub-stall and super-stall loads, a conclusion which is likely to have implications in other situations involving collective effects of many motors.
journal_name
Phys Bioljournal_title
Physical biologyauthors
Bhat D,Gopalakrishnan Mdoi
10.1088/1478-3975/9/4/046003subject
Has Abstractpub_date
2012-08-01 00:00:00pages
046003issue
4eissn
1478-3967issn
1478-3975journal_volume
9pub_type
杂志文章相关文献
PHYSICAL BIOLOGY文献大全abstract::Cell signaling is achieved predominantly by reversible phosphorylation-dephosphorylation reaction cascades. Up until now, circuits conferring adaptation have all required the presence of a cascade with some type of closed topology: negative-feedback loop with a buffering node, or incoherent feed-forward loop with a pr...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/8/4/046005
更新日期:2011-08-01 00:00:00
abstract::Computer simulations of beta-hairpin folding are relatively difficult, especially those based on the explicit water model. This greatly limits the complete analysis and understanding of their folding mechanisms. In this paper, we use the generalized Born/solvent accessible implicit solvent model to simulate the foldin...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/3/3/001
更新日期:2006-08-24 00:00:00
abstract::Electrostatic interaction is the driving force for the encapsulation by virus coat proteins of nanoparticles such as quantum dots, gold particles and magnetic beads for, e.g., imaging and therapeutic purposes. In recent experimental work, Daniel et al (2010 ACS Nano 4 3853-60) found the encapsulation efficiency to sen...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/9/6/066004
更新日期:2012-12-01 00:00:00
abstract::How interactions between mechanics and biochemistry lead to the emergence of complex cell and tissue organization is an old question that has recently attracted renewed interest from biologists, physicists, mathematicians and computer scientists. Rapid advances in optical physics, microscopy and computational image an...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/abd0db
更新日期:2020-12-04 00:00:00
abstract::A cluster of neural crest cells (NCCs) may chemotax up a shallow external gradient to which a single cell is unresponsive. To explain this intriguing 'group advantage', we propose a chemo-mechanical model based on the signaling proteins Rac1 and RhoA. We represent each cell as a polygon with nodes connected by elastic...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/ab71f1
更新日期:2020-03-10 00:00:00
abstract::Chemotaxis is the process by which cells sense changes in their chemical environment and move towards more favorable conditions. In divergent species of bacteria, the chemotaxis proteins localize to the poles of the cell and information is transferred to the flagellar motors through the phosphorylation of a soluble pr...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/2/3/002
更新日期:2005-07-14 00:00:00
abstract::Protein-protein interactions are central to biology and, in this 'post-genomic era', prediction of these interactions has become the goal of many computational efforts. Close inspection of even relatively simple biological regulatory circuitry reveals multiple levels of control of the contributing protein interactions...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/2/2/S07
更新日期:2005-06-01 00:00:00
abstract::This special issue consists of 11 original papers that elaborate on work presented at the Fourth Annual q-bio Conference on Cellular Information Processing, which was held on the campus of St John's College in Santa Fe, New Mexico, USA, 11-14 August 2010. Now in its fourth year, the q-bio conference has changed consid...
journal_title:Physical biology
pub_type:
doi:10.1088/1478-3975/8/5/050301
更新日期:2011-10-01 00:00:00
abstract::Trauma arising from landmines and improvised explosive devices promotes heterotopic ossification, the formation of extra-skeletal bone in non-osseous tissue. To date, experimental platforms that can replicate the loading parameter space relevant to improvised explosive device and landmine blast wave exposure have not ...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/ab7d1c
更新日期:2020-08-12 00:00:00
abstract::Recent advances in clinical medicine have elucidated two significantly different subtypes of glioblastoma which carry very different prognoses, both defined by mutations in isocitrate dehydrogenase-1 (IDH-1). The mechanistic consequences of this mutation have not yet been fully clarified, with conflicting opinions exi...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/8/1/015016
更新日期:2011-02-01 00:00:00
abstract::Asexual reproduction in multicellular organisms is a complex biophysical process that is not yet well understood quantitatively. Here, we report a detailed population study for the asexual freshwater planarian Schmidtea mediterranea, which can reproduce via transverse fission due to a large stem cell contingent. Our l...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/8/2/026003
更新日期:2011-04-01 00:00:00
abstract::In recent years, by using modern imaging techniques, scientists have found evidence of collaboration between different types of stem cells (SCs), and proposed a bi-compartmental organization of the SC niche. Here we create a class of stochastic models to simulate the dynamics of such a heterogeneous SC niche. We consi...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/12/5/055001
更新日期:2015-07-31 00:00:00
abstract::Successful biological development via spatial regulation of cell differentiation relies on the action of multiple signaling molecules that are known as morphogens. It is now well-established that signaling molecules create non-uniform concentration profiles, morphogen gradients, that activate different genes, leading ...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/12/2/026006
更新日期:2015-04-17 00:00:00
abstract::Directed cell migration often involves at least two types of cell motility that include multicellular streaming and chain migration. However, what is unclear is how cell contact dynamics and the distinct microenvironments through which cells travel influence the selection of one migratory mode or the other. The embryo...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/10/3/035003
更新日期:2013-06-01 00:00:00
abstract::Cancer may result from localized failure of instructive cues that normally orchestrate cell behaviors toward the patterning needs of the organism. Steady-state gradients of transmembrane voltage (V(mem)) in non-neural cells are instructive, epigenetic signals that regulate pattern formation during embryogenesis and mo...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/9/6/065002
更新日期:2012-12-01 00:00:00
abstract::The detection of gravity plays a fundamental role during the growth and evolution of plants. Although progress has been made in our understanding of the molecular, cellular and physical mechanisms involved in the gravity detection, a coherent scenario consistent with all the observations is still lacking. In this spec...
journal_title:Physical biology
pub_type: 杂志文章,评审
doi:10.1088/1478-3975/aa6876
更新日期:2017-05-23 00:00:00
abstract::Cells moving on a two dimensional substrate generate motion by polymerizing actin filament networks inside a flat membrane protrusion. New filaments are generated by branching off existing ones, giving rise to branched network structures. We investigate the force-extension relation of branched filaments, grafted on an...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/12/4/046007
更新日期:2015-06-04 00:00:00
abstract::Epigenetic mechanisms of silencing via heritable chromatin modifications play a major role in gene regulation and cell fate specification. We consider a model of epigenetic chromatin silencing in budding yeast and study the bifurcation diagram and characterize the bistable and the monostable regimes. The main focus of...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/10/3/036005
更新日期:2013-06-01 00:00:00
abstract::Thrombosis accounts for 80% of deaths in patients with diabetes mellitus. Diabetic patients demonstrate tortuous microvessels and larger than normal platelets. Large platelets are associated with increased platelet activation and thrombosis, but the physical effects of large platelets in the microscale processes of th...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/10/5/056003
更新日期:2013-10-01 00:00:00
abstract::A central question in eukaryotic cell biology asks, during cell division, how is the growth and distribution of organelles regulated to ensure each daughter cell receives an appropriate amount. For vacuoles in budding yeast, there are well described organelle-to-cell size scaling trends as well as inheritance mechanis...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/aba510
更新日期:2020-10-09 00:00:00
abstract::We present a new particle tracking software algorithm designed to accurately track the motion of low-contrast particles against a background with large variations in light levels. The method is based on a polynomial fit of the intensity around each feature point, weighted by a Gaussian function of the distance from th...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/4/3/008
更新日期:2007-10-09 00:00:00
abstract::Intermolecular interactions became an inherent part of the structure-function paradigm. Therefore, the generalized concept of protein stability and interactions should consider the balance of stabilizing forces working in different types of intermolecular interactions. We consider here two 'extremes' of protein intera...
journal_title:Physical biology
pub_type: 杂志文章,评审
doi:10.1088/1478-3975/8/3/035002
更新日期:2011-06-01 00:00:00
abstract::By combining optical tweezers-assisted dynamic force spectroscopy experiments with fluorescence activated cell sorting (FACS), we demonstrate a new approach to reducing the data variance in measuring receptor-ligand interactions on a single molecule level by ensuring similar coating densities. Therefore, the carboxyfl...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/10/4/046004
更新日期:2013-08-01 00:00:00
abstract::Bistable regulatory elements enhance heterogeneity in cell populations and, in multicellular organisms, allow cells to specialize and specify their fate. Our study demonstrates that in a system of bistable genetic switch, the noise characteristics control in which of the two epigenetic attractors the cell population w...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/10/3/035007
更新日期:2013-06-01 00:00:00
abstract::The proper functioning of multicellular organisms requires the robust establishment of precise proportions between distinct cell types. This developmental differentiation process typically involves intracellular regulatory and stochastic mechanisms to generate cell-fate diversity as well as intercellular signaling mec...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/13/2/026007
更新日期:2016-05-11 00:00:00
abstract::The field of tissue engineering aims to produce living, biological constructs which possess the appropriate spatial ordering of cells and their extra cellular matrix products. The complexity of a single cell and its interactions in a large collective have made development of useful models to assist in tissue culture d...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/5/1/016007
更新日期:2008-04-01 00:00:00
abstract::This report presents a simple model that describes the motion of a single Dictyostelium discoideum cell exposed to a traveling wave of cyclic adenosine monophosphate (cAMP). The model incorporates two types of responses to stimulation by cAMP: the changes in the polarity and motility of the cell. The periodic change i...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/12/2/026004
更新日期:2015-03-19 00:00:00
abstract::Self-organization processes in multicellular aggregates of bacteria and amoebae offer fascinating insights into the evolution of cooperation and differentiation of cells. During myxobacterial development a variety of spatio-temporal patterns emerges such as counterpropagating waves of cell density that are known as ri...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/3/2/006
更新日期:2006-06-23 00:00:00
abstract::The source of increased stability in proteins from organisms that thrive in extreme thermal environments is not well understood. Previous experimental and theoretical studies have suggested many different features possibly responsible for such thermostability. Many of these thermostabilizing mechanisms can be accounte...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/7/1/016002
更新日期:2009-12-11 00:00:00
abstract::This paper explores the potential for simplicity to reveal new biological understanding. Borrowing selectively from physics thinking, and contrasting with Crick's reductionist philosophy, the author argues that greater emphasis on simplicity is necessary to advance biology and its applications. ...
journal_title:Physical biology
pub_type: 杂志文章
doi:10.1088/1478-3975/12/6/063002
更新日期:2015-12-30 00:00:00