Rac1 selectively binds a specific lamellipodin isoform via a noncanonical helical interface
Tong Gao1, Pingfeng Zhang1, Alison M Kurimchak1
1Cancer Signaling and Microenvironment Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA.
None:
Lamellipodin (Lpd) is a multifunctional adapter protein that regulates cell migration and adhesion by recruiting Ena/VASP proteins to the leading edge and modulating actin polymerization. The interaction of Lpd and Rho family or Ras family GTPases is crucial for regulating actin dynamics. Contrary to previous assumptions that the main Lpd isoform interacts with Rac1, here we show that strong and specific binding to Rac1 is instead mediated by the short isoform Lpds. This interaction is dependent on Rac1's GTPase activity and a short insertion (cs2) within the coiled-coil region unique to the Lpds isoform. Structural modeling and mutagenesis analyses further reveal that Lpds engages Rac1 through a noncanonical, single-helix binding mode distinct from the canonical helical-pair configuration. Our results uncover a novel isoform-dependent GTPase:effector binding mode for Rac1-driven actin dynamics, with implications for therapeutic targeting in Rac1-associated cancer progression.
More Related Videos
12:15The C. elegans Intestine As a Model for Intercellular Lumen Morphogenesis and In Vivo Polarized Membrane Biogenesis at the Single-cell Level: Labeling by Antibody Staining, RNAi Loss-of-function Analy
Published on: October 3, 2017
10:50Isolation of Labile Multi-protein Complexes by in vivo Controlled Cellular Cross-Linking and Immuno-magnetic Affinity Chromatography
Published on: March 9, 2010
Related Concept Videos
Mechanism of Lamellipodia Formation
Rab Proteins
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...
Intracellular Signaling Affects Focal Adhesions
Some...
Catenins
Catenins in Cell Junctions
Catenins bind to cell adhesion molecules such as cadherins and link them to different cytoskeletal proteins depending on the type of cell junction. At the...
Rab Cascades
Mechanism of Filopodia Formation
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
