Topic
SCAR complex
About: SCAR complex is a research topic. Over the lifetime, 20 publications have been published within this topic receiving 1884 citations.
Papers
TL;DR: It is proposed that Rac1 and Nck cause dissociation of the WAVE1 complex, which releases activeWAVE1–HSPC300 and leads to actin nucleation.
Abstract: Rac signalling to actin -- a pathway that is thought to be mediated by the protein Scar/WAVE (WASP (Wiskott-Aldrich syndrome protein)-family verprolin homologous protein -- has a principal role in cell motility. In an analogous pathway, direct interaction of Cdc42 with the related protein N-WASP stimulates actin polymerization. For the Rac-WAVE pathway, no such direct interaction has been identified. Here we report a mechanism by which Rac and the adapter protein Nck activate actin nucleation through WAVE1. WAVE1 exists in a heterotetrameric complex that includes orthologues of human PIR121 (p53-inducible messenger RNA with a relative molecular mass (M(r)) of 140,000), Nap125 (NCK-associated protein with an M(r) of 125,000) and HSPC300. Whereas recombinant WAVE1 is constitutively active, the WAVE1 complex is inactive. We therefore propose that Rac1 and Nck cause dissociation of the WAVE1 complex, which releases active WAVE1-HSPC300 and leads to actin nucleation.
908 citations
TL;DR: In Drosophila cells, SCAR is regulated by Abi, Kette, and Sra1, components of a conserved regulatory SCAR complex that help to ensure that Arp2/3 activation and the generation of actin-based protrusions remain strictly dependant on local GTPase signaling.
372 citations
TL;DR: PIR121 appears to inhibit the activity of SCAR in the absence of activating signals, suggesting that active SCAR protein released from the inhibitory complex is rapidly removed and that this is an important and novel mechanism for controlling actin dynamics.
161 citations
TL;DR: A pathway through which roots of Arabidopsis thaliana directly perceive light to promote their elongation is presented, and biochemical explanation for light-induced promotion of root elongation by the ARP2/3-SCAR complex is provided.
Abstract: The ARP2/3 complex, a highly conserved nucleator of F-actin, and its activator, the SCAR complex, are essential for growth in plants and animals. In this article, we present a pathway through which roots of Arabidopsis thaliana directly perceive light to promote their elongation. The ARP2/3-SCAR complex and the maintenance of longitudinally aligned F-actin arrays are crucial components of this pathway. The involvement of the ARP2/3-SCAR complex in light-regulated root growth is supported by our finding that mutants of the SCAR complex subunit BRK1/HSPC300, or other individual subunits of the ARP2/3-SCAR complex, showed a dramatic inhibition of root elongation in the light, which mirrored reduced growth of wild-type roots in the dark. SCAR1 degradation in dark-grown wild-type roots by constitutive photomorphogenic 1 (COP1) E3 ligase and 26S proteasome accompanied the loss of longitudinal F-actin and reduced root growth. Light perceived by the root photoreceptors, cryptochrome and phytochrome, suppressed COP1-mediated SCAR1 degradation. Taken together, our data provide a biochemical explanation for light-induced promotion of root elongation by the ARP2/3-SCAR complex.
126 citations
TL;DR: It is proposed that temporally and spatially regulated actin nucleation by the Rac-WAVE/SCAR-Arp2/3 pathway is required for epithelial cell organization and movements during morphogenesis.
118 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2019 | 1 |
| 2016 | 2 |
| 2013 | 2 |
| 2012 | 2 |
| 2011 | 1 |
| 2009 | 2 |