SUPPLEMENTARY DATA
The Interplay of Cell-cell and Cell-substrate Adhesion in Collective
Cell Migration
Chenlu Wang, Sagar Chowdhury, Meghan Driscoll, Carole A. Parent, S.K. Gupta,
Wolfgang Losert
SUPPLEMENTARY FIGURES AND LEGENDS
Figure S1: Comparison of the extracted motion tracks between overall cell movement
(original movement) and the active cell movement (corrected movement) on PEG
coated surfaces.
Figure S2: Speed of cells with both passive motion and active motion varies during
aggregation, whereas the speed of cells with subtraction of passive motion remains
steady during aggregation
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Figure S3: Comparison of frequency of protrusion waves that generated on individual
adherent cells and individual suspended cells. Data averaged from over 10 cells on
each condition. Error bar: standard deviation of the mean.
Figure S4: Cells migrate on glass surface mainly polymerize actin at their leading
edges. AX3 (WT) cells and AX3-Lifeact-RFP cells were evenly mixed and plated on
glass surface. (a), Bright field, fluorescent, and composite images show a AX3 (WT)
cell is migrating on glass surface, followed by an AX3-Lifeact-RFP cell, which has
more F-actin at its front. (b), Bright field, fluorescent, and composite images show an
AX3-Lifeact-RFP cell is leading an AX3 (WT) cell during migration. There is no
notable F-actin enrichment at the back of the AX3-Lifeact-RFP cell.
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SUPPLEMENTARY MOVIE LEGENDS
Movie 1: cell-surface adhesion alter self-aggregation dynamics.
Representative time-lapse movie of WT cells aggregating on glass and on PEG-coated
surfaces, as filmed by confocal microscopy. On glass, the aggregation process
involves large streams, and on PEG surface, aggregation involves cells clumping into
small groups, which in turn merge into larger groups.
Movie 2: with subtraction of passive movement, corrected movement tracks
show the aggregation of cells towards an aggregation center.
Time-lapse movie of comparison of the extracted motion tracks between overall cell
movement (original movement) and the active cell movement (corrected movement)
on PEG coated surfaces.
Movie 3: cell-cell adhesion alter multicellular streaming process.
Representative time-lapse movie of WT cells migrating on glass surfaces in medium
of different ion concentration, as filmed by phase contrast microscopy. Cell-cell
adhesion is inhibited at different level.
Movie 4, without adhesions, suspended cells retain their polarity and motility.
Representative time-lapse movie of WT cells suspended in DI water, as filmed by
confocal microscopy. Cells do not form cell-cell adhesion and cell-surface adhesion
because of electrostatic repulsion between cell membrane and glass surface, both of
which are negative charged. However, these cells retain their polarity and motility.
Movie 5: boundaries of a migrating adherent cell are extracted and colored by
curvature and fluorescence intensity, respectively.
(a) A representative individual AX3-Lifeact-RFP cell migrating on a glass surface. (b)
The representative cell with the cell boundary, colored by curvature, overlaid. Red
represents regions of positive curvature, and blue represents regions of negative
curvature. (c) The representative cell with the cell boundary, colored by the intensity
of nearby actin fluorescence, overlaid. Red represents region of high fluorescence
intensity, and blue represents regions of low fluorescence intensity.
Movie 6: boundaries of a suspended cell are extracted and colored by curvature
and fluorescence intensity, respectively.
(a) A representative individual AX3-Lifeact-RFP cell is suspended on a PEG coated
surface. (b) The representative cell with the cell boundary, colored by curvature,
overlaid. Red represents regions of positive curvature, and blue represents regions of
negative curvature. (c) The representative cell with the cell boundary, colored by the
intensity of nearby actin fluorescence, overlaid. Red represents region of high
fluorescence intensity, and blue represents regions of low fluorescence intensity.
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Movie 7: adherent cells move in a head-to-tail fashion on glass.
A movie of a representative pair of AX3 cells that are head-to-tail aligned and
migrating on glass using the same path. (Cells were cytosolically stained green and
orange.)
Movie 8: suspended cells align in a tail-to-tail fashion on PEG-coated surface.
A movie of a representative pair of AX3 cells suspended over a PEG-coated surface.
(Cells were cytosolically stained green.)
Movie 9: cell-substrate contact can induce a switch in cell polarity.
A 5 μm glass beads is pushed by optical tweezers and is adhered to the leading edge
of a suspended cell, the cell rapidly loses its polarity and generates a new leading edge
far from the cell-bead contact region.
Movie 10: F-actin enriches at the contact region of a pair of cells on glass.
A fluorescence movie of a representative pair of AX3-Lifeact-RFP cells migrating
with front-to-back alignment on glass. Actin mainly polymerizes at the front of the
leading cell and at the contact region of the two cells.
Movie 11: actin polymerize at the far edges of a pair of cells on PEG-coated
surface.
A fluorescence movie of a representative pair of AX3-Lifeact-RFP cells that display
back-to-back alignment on PEG-coated surface. In these cells, actin mostly
polymerizes at the far edges (free ends) of both cells, with no significant F-actin
enrichment in the cell-cell contact region.
Movie 12: cell-substrate contact changes spatial distribution of F-actin within
cells.
Using optical tweezers, a 5 μm glass beads is adhered to a recently generated
protrusion on the cell, and sticks on the membrane of the cell. Upon contact with the
bead, F-actin is enriched at the end of the cell opposite to the cell-bead contact region.
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