- PMID:
12925274
- Authors:
- Antipenko A, Himanen JP, van Leyen K, Nardi-Dei V, Lesniak J, Barton WA, Rajashankar KR, Lu M, Hoemme C, Puschel AW, Nikolov DB
- Title:
- Structure of the semaphorin-3A receptor binding module.
- Journal:
- Neuron. 2003 Aug 14;39(4):589-98.
- Abstract:
- The semaphorins are a large group of extracellular proteins involved in a variety of processes during development, including neuronal migration and axon guidance. Their distinctive feature is a conserved 500 amino acid semaphorin domain, a ligand-receptor interaction module also present in plexins and scatter-factor receptors. We report the crystal structure of a secreted 65 kDa form of Semaphorin-3A (Sema3A), containing the full semaphorin domain. Unexpectedly, the semaphorin fold is a variation of the beta propeller topology. Analysis of the Sema3A structure and structure-based mutagenesis data identify the neuropilin binding site and suggest a potential plexin interaction site. Based on the structure, we present a model for the initiation of semaphorin signaling and discuss potential similarities with the signaling mechanisms of other beta propeller cell surface receptors, such as integrins and the LDL receptor.