Structural bases for CRMP function in plexin-dependent semaphorin3A signaling

• Published in: The EMBO journal 2004-01, Vol.23 (1), p.9-22
• Main Authors: Deo, Rahul C, Schmidt, Eric F, Elhabazi, Abdellah, Togashi, Hideaki, Burley, Stephen K, Strittmatter, Stephen M
• Format: Article
• Language: English
• Subjects: Alanine - metabolism; Amino Acid Sequence; Amino Acid Substitution; Animals; BASIC BIOLOGICAL SCIENCES; BIOLOGICAL FUNCTIONS; Cell Adhesion Molecules - metabolism; CELL CONSTITUENTS; Cell Line; Chick Embryo; Chlorocebus aethiops; COS Cells; CRMP; Crystallography, X-Ray; EMBO27; EMBO40; Ganglia, Spinal - metabolism; Humans; Hydrogen Bonding; Immunophilins - metabolism; Mice; Models, Molecular; Molecular Sequence Data; MORPHOLOGY; Mutagenesis, Site-Directed; NATIONAL SYNCHROTRON LIGHT SOURCE; Nerve Tissue Proteins - chemistry; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - metabolism; neuropilin; Phosphoproteins - chemistry; Phosphoproteins - genetics; Phosphoproteins - metabolism; plexin; Protein Structure, Secondary; Protein Structure, Tertiary; Receptors, Cell Surface - metabolism; Recombinant Fusion Proteins - metabolism; semaphorin; Semaphorin-3A - metabolism; Sequence Homology, Amino Acid; Signal Transduction; Structure-Activity Relationship
• ISSN: 0261-4189; 1460-2075
• DOI: 10.1038/sj.emboj.7600021

Collapsin response mediator proteins (CRMPs) are cytosolic phosphoproteins involved in neuronal differentiation and axonal guidance. CRMP2 was previously shown to mediate the repulsive effect of Sema3A on axons and to participate in axonal specification. The X‐ray crystal structure of murine CRMP1 was determined at 2.1 Å resolution and demonstrates that CRMP1 is a bilobed ‘lung‐shaped’ protein forming a tetrameric assembly. Structure‐based mutagenesis of surface‐exposed residues was employed to map functional domains. As a rapid assay for CRMP, we exploited a reconstituted Sema3A signaling system in COS‐7 cells expressing the receptor components Neuropilin1 and PlexinA1 (NP1/PlexA1). In these cells, CRMP and PlexA1 form a physical complex that is reduced in amount by NP1 but enhanced by Sema3A/NP1. Furthermore, CRMP accelerates Sema3A‐induced cell contraction. Alanine substitutions in one domain of CRMP1 produce a constitutively active protein that causes Sema3A‐independent COS‐7 contraction. This mutant CRMP mimics the DRG neurite outgrowth‐inhibiting effects of Sema3A and reduces Sema3A‐induced axonal repulsion. These data provide a structural view of CRMP function in Plex‐dependent Sema3A signaling.