Structural bases for CRMP function in plexin-dependent semaphorin3A signaling.
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 A 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.
Deo
Rahul C
RC
Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA.
Schmidt
Eric F
EF
Elhabazi
Abdellah
A
Togashi
Hideaki
H
Burley
Stephen K
SK
Strittmatter
Stephen M
SM
D000409:Alanine / Q000378:metabolism; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D019556:COS Cells; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002460:Cell Line; D002642:Chick Embryo; D002522:Chlorocebus aethiops; D018360:Crystallography, X-Ray; D005727:Ganglia, Spinal / Q000378:metabolism; D006801:Humans; D006860:Hydrogen Bonding; D020104:Immunophilins / Q000378:metabolism; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D040121:Semaphorin-3A / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013329:Structure-Activity Relationship; D000098855:Collapsin Response Mediator Protein 1
D015815:Cell Adhesion Molecules; D009419:Nerve Tissue Proteins; C492116:PLXNA1 protein, human; D010750:Phosphoproteins; C492114:Plxna1 protein, mouse; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; D040121:Semaphorin-3A; D000098855:Collapsin Response Mediator Protein 1; C091529:plexin; D020104:Immunophilins; D000409:Alanine