The semaphorin receptor plexin-B1 specifically interacts with active Rac in a ligand-dependent manner. Proc Natl Acad Sci U S A 2000 Nov 07;97(23):12457-62
Date
10/18/2000Pubmed ID
11035813Pubmed Central ID
PMC18785DOI
10.1073/pnas.220421797Scopus ID
2-s2.0-0033739987 (requires institutional sign-in at Scopus site) 155 CitationsAbstract
Semaphorin molecules serve as axon guidance signals that regulate the navigation of neuronal growth cones. Semaphorins have also been implicated in other biological processes, including the immune response. Plexins, acting either alone or in complex with neuropilins, have recently been identified as functional semaphorin receptors. However, the mechanisms of signal transduction by plexins remain largely unknown. We have demonstrated a direct interaction between plexin-B1 and activated Rac. Rac specifically interacts with the cytosolic domain of plexin-B1, but not with that of plexin-A3 or -C1. Neither RhoA nor Cdc42 interacts with plexin-B1, indicating that the Rac/plexin-B1 interaction is highly specific. The binding of GTP and the integrity of the Rac effector domain are required for the interaction with plexin-B1. Furthermore, we have identified that a Cdc42/Rac interactive binding (CRIB) motif in the cytosolic domain of plexin-B1 is essential for its interaction with active Rac. We have also observed that the semaphorin CD100, a ligand for plexin-B1, stimulates the interaction between plexin-B1 and active Rac. Our results support a model by which activated Rac plays a role in mediating semaphorin signals, resulting in reorganization of actin cytoskeletal structure.
Author List
Vikis HG, Li W, He Z, Guan KLMESH terms used to index this publication - Major topics in bold
Amino Acid MotifsAntigens, CD
Binding Sites
Cell Line
Humans
Ligands
Membrane Glycoproteins
Nerve Tissue Proteins
Receptors, Cell Surface
Semaphorins
Structure-Activity Relationship
rac1 GTP-Binding Protein
