title: Plexin-A1 and plexin-B1 specifically interact at their cytoplasmic domains.
abstract: Semaphorin 3A (Sema3A) is a member of semaphorins and functions as an axonal repulsive guidance molecule. Neuropilin-1 and plexin-As form receptor complexes for Sema3A and plexin-As are thought to initiate the intracellular signaling cascade. However, the molecule by which plexin-As transduce their signal is not well understood. We searched molecules that interact with intracellular domains of plexin-A1 by yeast two-hybrid screening and identified a 349 amino acid fragment of plexin-B1 as a plexin-A1 interacting protein. We, then, cloned mouse plexin-B1 and confirmed their interaction in a mammalian expression system. Plexin-B1 physically associated with plexin-A1, but not with plexin-A2 or A3. Northern blot analysis showed the expression of both plexin-A1 and B1 in adult brain. We propose that plexin-A1 and B1 interact in the adult brain and transduce Sema3A signaling in cooperation.
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of Tokyo, CREST, Bunkyo-ku, Hongo, Tokyo 113-0033, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Usui
authors.forename: Masahiko
authors.initials: M
authors.lastname: Taniguchi
authors.forename: Takehiko
authors.initials: T
authors.lastname: Yokomizo
authors.forename: Takao
authors.initials: T
authors.lastname: Shimizu
mesh_terms: D000818:Animals; D003593:Cytoplasm / Q000737:chemistry; D046911:Macromolecular Substances; D051379:Mice; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D039942:Neuropilin-1 / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D040121:Semaphorin-3A / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D014018:Tissue Distribution; D020798:Two-Hybrid System Techniques; D020744:rac GTP-Binding Proteins / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000378:metabolism
chemical_list: D046911:Macromolecular Substances; D009419:Nerve Tissue Proteins; C492114:Plxna1 protein, mouse; C492118:Plxnb1 protein, mouse; D011956:Receptors, Cell Surface; D040121:Semaphorin-3A; D039942:Neuropilin-1; D020744:rac GTP-Binding Proteins; D020741:rho GTP-Binding Proteins