title: Semaphorin4F interacts with the synapse-associated protein SAP90/PSD-95.
abstract: Semaphorins are a family of secreted and membrane-associated proteins involved in growth cone guidance during development. Here, we describe the interaction of Semaphorin4F (Sema4F) with the post-synaptic density protein SAP90/PSD-95. Using the yeast two-hybrid system and coprecipitation assays we were able to show an interaction between the extreme C-terminus of Sema4F and the PDZ domains of SAP90/PSD-95. Heterologous coexpression of a chimeric EphrinB1/Semaphorin4F protein with SAP90/PSD-95 in COS cells leads to translocation of SAP90/PSD-95 from the cytosol to the membrane. Deletion analysis shows that this translocation activity of Sema4F is completely dependent on the presence of the last three C-terminal amino acids. In addition, Sema4F immunoreactivity is present in synaptosome fractions and enriched in post-synaptic density fractions. Consistently, in cultured hippocampal neurons, we demonstrate punctate colocalization of Sema4F and SAP90/PSD-95 in dendrites, furthermore we found colocalization of Sema4F with synapsin1 suggesting a synaptic localization. Our data implicate a new functional context for semaphorins at glutamatergic synapses.
authors.affiliation: Department of Molecular Neurobiochemistry, Ruhr-University Bochum, Bochum, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Schultze
authors.forename: V
authors.initials: V
authors.lastname: Eulenburg
authors.forename: V
authors.initials: V
authors.lastname: Lessmann
authors.forename: L
authors.initials: L
authors.lastname: Herrmann
authors.forename: T
authors.initials: T
authors.lastname: Dittmar
authors.forename: E D
authors.initials: ED
authors.lastname: Gundelfinger
authors.forename: R
authors.initials: R
authors.lastname: Heumann
authors.forename: K S
authors.initials: KS
authors.lastname: Erdmann
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002458:Cell Fractionation; D002478:Cells, Cultured; D036387:Ephrin-B1; D006624:Hippocampus / Q000166:cytology; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D000074407:SAP90-PSD95 Associated Proteins; D016415:Sequence Alignment; D014162:Transfection; D020798:Two-Hybrid System Techniques
chemical_list: D002352:Carrier Proteins; D036387:Ephrin-B1; D008565:Membrane Proteins; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; D000074407:SAP90-PSD95 Associated Proteins; C118124:SEMA4F protein, human; C491229:Sema3f protein, mouse; C485552:Sema4f protein, mouse