TY - JOUR
T1 - Cytoplasmic flows as signatures for the mechanics of mitotic positioning
AU - Nazockdast, Ehssan
AU - Rahimian, Abtin
AU - Needleman, Daniel
AU - Shelley, Michael
N1 - Funding Information:
We thank Sebastian Füerthauer, Hassan Masoud, Tong Gao, Michael O’Neal, and Carlos Garzon-Coral for helpful discussions. We acknowledge support from National Institutes of Health Grant 1R01GM104976-01. E.N. and M.S. acknowledge support from National Institutes of Health Grant 1R01GM104976-01 and National Science Foundation Grants DMS 1463962 and DMS-1620331. A.R. acknowledges the support of the National Science Foundation through Grant DMS-1320621.
PY - 2017/11/7
Y1 - 2017/11/7
N2 - The proper positioning of mitotic spindle in the single-cell Caenorhabditis elegans embryo is achieved initially by the migration and rotation of the pronuclear complex (PNC) and its two associated astral microtubules (MTs). Pronuclear migration produces global cytoplasmic flows that couple the mechanics of all MTs, the PNC, and the cell periphery with each other through their hydrodynamic interactions (HIs). We present the first computational study that explicitly accounts for detailed HIs between the cytoskeletal components and demonstrate the key consequences of HIs for the mechanics of pronuclear migration. First, we show that, because of HIs between the MTs, the cytoplasm-filled astral MTs behave like a porous medium, with its permeability decreasing with increasing the number of MTs. We then directly study the dynamics of PNC migration under various force-Transduction models, including the pushing or pulling of MTs at the cortex and the pulling of MTs by cytoplasmically bound force generators. Although achieving proper position and orientation on reasonable time scales does not uniquely choose a model, we find that each model produces a different signature in its induced cytoplasmic flow. We suggest that cytoplasmic flows can be used to differentiate between mechanisms.
AB - The proper positioning of mitotic spindle in the single-cell Caenorhabditis elegans embryo is achieved initially by the migration and rotation of the pronuclear complex (PNC) and its two associated astral microtubules (MTs). Pronuclear migration produces global cytoplasmic flows that couple the mechanics of all MTs, the PNC, and the cell periphery with each other through their hydrodynamic interactions (HIs). We present the first computational study that explicitly accounts for detailed HIs between the cytoskeletal components and demonstrate the key consequences of HIs for the mechanics of pronuclear migration. First, we show that, because of HIs between the MTs, the cytoplasm-filled astral MTs behave like a porous medium, with its permeability decreasing with increasing the number of MTs. We then directly study the dynamics of PNC migration under various force-Transduction models, including the pushing or pulling of MTs at the cortex and the pulling of MTs by cytoplasmically bound force generators. Although achieving proper position and orientation on reasonable time scales does not uniquely choose a model, we find that each model produces a different signature in its induced cytoplasmic flow. We suggest that cytoplasmic flows can be used to differentiate between mechanisms.
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U2 - 10.1091/mbc.E16-02-0108
DO - 10.1091/mbc.E16-02-0108
M3 - Article
C2 - 28331070
AN - SCOPUS:85033445073
SN - 1059-1524
VL - 28
SP - 3261
EP - 3270
JO - Molecular biology of the cell
JF - Molecular biology of the cell
IS - 23
ER -