The Arp2/3 complex is required for lamellipodia extension and directional fibroblast cell migration

Stowers Institute for Medical Research, Kansas City, MO 64110, USA.
The Journal of Cell Biology (Impact Factor: 9.69). 04/2012; 197(2):239-51. DOI: 10.1083/jcb.201112113
Source: PubMed

ABSTRACT The Arp2/3 complex nucleates the formation of the dendritic actin network at the leading edge of motile cells, but it is still unclear if the Arp2/3 complex plays a critical role in lamellipodia protrusion and cell motility. Here, we differentiated motile fibroblast cells from isogenic mouse embryonic stem cells with or without disruption of the ARPC3 gene, which encodes the p21 subunit of the Arp2/3 complex. ARPC3(-/-) fibroblasts were unable to extend lamellipodia but generated dynamic leading edges composed primarily of filopodia-like protrusions, with formin proteins (mDia1 and mDia2) concentrated near their tips. The speed of cell migration, as well as the rates of leading edge protrusion and retraction, were comparable between genotypes; however, ARPC3(-/-) cells exhibited a strong defect in persistent directional migration. This deficiency correlated with a lack of coordination of the protrusive activities at the leading edge of ARPC3(-/-) fibroblasts. These results provide insights into the Arp2/3 complex's critical role in lamellipodia extension and directional fibroblast migration.

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Available from: Jay R Unruh, Aug 16, 2015
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    • "However, the development of computational algorithms to analyze the vast amounts of data produced is lagging behind (Myers, 2012). The application of automated, unbiased , computational methods for morphodynamic quantification is rare, with the use of kymographs, for example, still popular (Suraneni et al., 2012; Ura et al., 2012; Wiggan et al., 2012; Dang et al., 2013). Such analyses are time consuming, subject to individual bias, and extract relatively low levels of information . "
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    • "We also saw this stellate phenotype with filopodia in MTLn3 cells treated with CK666 (Fig. 2 A), and, as we previously reported, in Drosophila S2 cells with RNAi knockdown of Arp2 and expression of Arp2-T237/238A-Y202A (LeClaire et al., 2008). Additionally, the stellate phenotype is seen in fibroblasts lacking ARPC2 (Wu et al., 2012) or ARPC3 (Suraneni et al., 2012) subunits. Hence, inhibiting the Arp2/3 complex may unmask actin assemblies regulated by other nucleators such as formins, which can generate contractile actin filaments. "
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    • "An exogenous gradient of human hepatocyte growth factor (hHGF; Preprotech, 100-39), at a final concentration of 100 ng/ml, was then applied to the top chamber. This gradient has been shown to be stable for up to 48 h post-application [Suraneni et al., 2012]. Cells were further cultured within an incubated chamber unit (37°C, 5% CO 2 ) of the Zeiss 710 LSM confocal microscope and DIC images were captured every 10 min for 16 h with the 10Â objective. "
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