Ena/VASP proteins mediate repulsion from ephrin ligands

TY - JOUR

T1 - Ena/VASP proteins mediate repulsion from ephrin ligands

AU - Evans, Iwan R

AU - Renne, Thomas

AU - Gertler, Frank B

AU - Nobes, Catherine D

PY - 2007/1/15

Y1 - 2007/1/15

N2 - Ena/VASP proteins negatively regulate cell motility and contribute to repulsion from several guidance cues; however, there is currently no evidence for a role downstream of Eph receptors. Eph receptors mediate repulsion from ephrins at sites of intercellular contact during several developmental migrations. For example, the expression of ephrin-Bs in posterior halves of somites restricts neural crest cell migration to the anterior halves. Here we show that ephrin-B2 destabilises neural crest cell lamellipodia when presented in a substrate-bound or soluble form. Our timelapse studies show that repulsive events are associated with the rearward collapse and subsequent loss of lamellipodia as membrane ruffles. We hypothesise that Ena/VASP proteins contribute to repulsion from ephrins by destabilising cellular protrusions and show that Ena/VASP-deficient fibroblasts exhibit reduced repulsion from both ephrin-A and ephrin-B stripes compared to wild-type controls. Moreover, when EphB4 and ephrin-B2 were expressed in neighbouring Swiss 3T3 fibroblasts, VASP and Mena co-accumulated with activated Eph receptors at protrusions formed by EphB4-expressing cells. Sequestration of Ena/VASP proteins away from the periphery of these cells inhibited Eph receptor internalisation, a process that facilitates repulsion. Our results suggest that Ena/VASP proteins regulate ephrin-induced Eph receptor signalling events, possibly by destabilising lamellipodial protrusions.

AB - Ena/VASP proteins negatively regulate cell motility and contribute to repulsion from several guidance cues; however, there is currently no evidence for a role downstream of Eph receptors. Eph receptors mediate repulsion from ephrins at sites of intercellular contact during several developmental migrations. For example, the expression of ephrin-Bs in posterior halves of somites restricts neural crest cell migration to the anterior halves. Here we show that ephrin-B2 destabilises neural crest cell lamellipodia when presented in a substrate-bound or soluble form. Our timelapse studies show that repulsive events are associated with the rearward collapse and subsequent loss of lamellipodia as membrane ruffles. We hypothesise that Ena/VASP proteins contribute to repulsion from ephrins by destabilising cellular protrusions and show that Ena/VASP-deficient fibroblasts exhibit reduced repulsion from both ephrin-A and ephrin-B stripes compared to wild-type controls. Moreover, when EphB4 and ephrin-B2 were expressed in neighbouring Swiss 3T3 fibroblasts, VASP and Mena co-accumulated with activated Eph receptors at protrusions formed by EphB4-expressing cells. Sequestration of Ena/VASP proteins away from the periphery of these cells inhibited Eph receptor internalisation, a process that facilitates repulsion. Our results suggest that Ena/VASP proteins regulate ephrin-induced Eph receptor signalling events, possibly by destabilising lamellipodial protrusions.

KW - 3T3 Cells

KW - Animals

KW - Cell Line, Transformed

KW - Cells, Cultured

KW - DNA-Binding Proteins

KW - Ephrin-A5

KW - Ephrin-B2

KW - Ephrins

KW - Fibroblasts

KW - Fluorescein-5-isothiocyanate

KW - Fluorescent Antibody Technique, Indirect

KW - Fluorescent Dyes

KW - Green Fluorescent Proteins

KW - Ligands

KW - Mice

KW - Mice, Knockout

KW - Microscopy, Video

KW - Neural Crest

KW - Phalloidine

KW - Pseudopodia

KW - Rats

KW - Rats, Sprague-Dawley

KW - Receptors, Eph Family

KW - Solubility

U2 - 10.1242/jcs.03333

DO - 10.1242/jcs.03333

M3 - SCORING: Journal article

C2 - 17179204

VL - 120

SP - 289

EP - 298

JO - J CELL SCI

JF - J CELL SCI

SN - 0021-9533

IS - Pt 2

ER -