title: Polarized targeting of peripheral membrane proteins in neurons.
abstract: Differential targeting of neuronal proteins to axons and dendrites is essential for directional information flow within the brain, however, little is known about this protein-sorting process. Here, we investigate polarized targeting of lipid-anchored peripheral membrane proteins, postsynaptic density-95 (PSD-95) and growth-associated protein-43 (GAP-43). Whereas the N-terminal palmitoylated motif of PSD-95 is necessary but not sufficient for sorting to dendrites, the palmitoylation motif of GAP-43 is sufficient for axonal targeting and can redirect a PSD-95 chimera to axons. Systematic mutagenesis of the GAP-43 and PSD-95 palmitoylation motifs indicates that the spacing of the palmitoylated cysteines and the presence of nearby basic amino acids determine polarized targeting by these two motifs. Similarly, the axonal protein paralemmin contains a C-terminal palmitoylated domain, which resembles that of GAP-43 and also mediates axonal targeting. These axonally targeted palmitoylation motifs also mediate targeting to detergent-insoluble glycolipid-enriched complexes in heterologous cells, suggesting a possible role for specialized lipid domains in axonal sorting of peripheral membrane proteins.
authors.affiliation: Department of Physiology and Program in Neuroscience, University of California at San Francisco School of Medicine, San Francisco, California 94143, USA.
authors.forename: A el-D
authors.initials: Ael-D
authors.lastname: El-Husseini
authors.forename: S E
authors.initials: SE
authors.lastname: Craven
authors.forename: S C
authors.initials: SC
authors.lastname: Brock
authors.forename: D S
authors.initials: DS
authors.lastname: Bredt
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001369:Axons / Q000378:metabolism; D019556:COS Cells; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D003902:Detergents / Q000494:pharmacology; D000076122:Disks Large Homolog 4 Protein; D019922:GAP-43 Protein / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D006624:Hippocampus / Q000166:cytology; D047908:Intracellular Signaling Peptides and Proteins; D050356:Lipid Metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D008565:Membrane Proteins; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D010169:Palmitic Acids / Q000378:metabolism; D017434:Protein Structure, Tertiary; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014162:Transfection
chemical_list: D018076:DNA, Complementary; D003902:Detergents; D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D019922:GAP-43 Protein; D047908:Intracellular Signaling Peptides and Proteins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D010169:Palmitic Acids; D011993:Recombinant Fusion Proteins; C033652:postsynaptic density proteins; D049452:Green Fluorescent Proteins