title: C-terminal synaptic targeting elements for postsynaptic density proteins ProSAP1/Shank2 and ProSAP2/Shank3.
abstract: Synapses are specialized contact sites mediating communication between neurons. Synaptogenesis requires the specific assembly of protein clusters at both sides of the synaptic contact by mechanisms that are barely understood. We studied the synaptic targeting of multi-domain proteins of the ProSAP/Shank family thought to serve as master scaffolding molecules of the postsynaptic density. In contrast to Shank1, expression of green-fluorescent protein (GFP)-tagged ProSAP1/Shank2 and ProSAP2/Shank3 deletion constructs in hippocampal neurons revealed that their postsynaptic localization relies on the integrity of the C-termini. The shortest construct that was perfectly targeted to synaptic sites included the last 417 amino acids of ProSAP1/Shank2 and included the C-terminal sterile alpha motif (SAM) domain. Removal of 54 residues from the N-terminus of this construct resulted in a diffuse distribution in the cytoplasm. Altogether, our data delineate a hitherto unknown targeting signal in both ProSAP1/Shank2 and ProSAP2/Shank3 and provide evidence for an implication of these proteins and their close homologue, Shank1, in distinct molecular pathways.
authors.affiliation: Institute of Anatomy and Cell Biology, University of Ulm, Albert Einstein Allee 11, 89081 Ulm, Germany. boeckers@medizin.uni-ulm.de
authors.forename: Tobias M
authors.initials: TM
authors.lastname: Boeckers
authors.forename: Thomas
authors.initials: T
authors.lastname: Liedtke
authors.forename: Christina
authors.initials: C
authors.lastname: Spilker
authors.forename: Thomas
authors.initials: T
authors.lastname: Dresbach
authors.forename: Jürgen
authors.initials: J
authors.lastname: Bockmann
authors.forename: Michael R
authors.initials: MR
authors.lastname: Kreutz
authors.forename: Eckart D
authors.initials: ED
authors.lastname: Gundelfinger
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D002478:Cells, Cultured; D049452:Green Fluorescent Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000235:genetics / Q000502:physiology; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis* / Q000235:genetics; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D013569:Synapses / Q000378:metabolism*; D014162:Transfection
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C113688:Bsn protein, rat; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; C120531:Shank1 protein, rat; C485686:Shank2 protein, rat; C120532:Shank3 protein, rat; D049452:Green Fluorescent Proteins