n-Sec1: A Neural-Specific Syntaxin-Binding Protein

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 91; no. 4; pp. 1445 - 1449
• Main Authors: Pevsner, Jonathan, Hsu, Shu-Chan, Scheller, Richard H.
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 15.02.1994; National Acad Sciences; National Academy of Sciences
• Subjects: Amino Acid Sequence; Amino acids; Analytical, structural and metabolic biochemistry; Animals; Antibodies; Antigens, Surface - metabolism; Base Sequence; Binding and carrier proteins; Biological and medical sciences; Blotting, Northern; Blotting, Western; Brain; Brain Chemistry; Cell membranes; Cell-Free System; Cellular biology; Cloning, Molecular; Complementary DNA; Cytosol - chemistry; Fundamental and applied biological sciences. Psychology; Fungal Proteins - genetics; Fungal Proteins - immunology; Gels; Golgi apparatus; Membranes - chemistry; Molecular Sequence Data; Munc18 Proteins; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - metabolism; Neurons; Peptide Fragments - metabolism; Protein Binding; Protein Biosynthesis; Proteins; Rats; Recombinant Fusion Proteins - biosynthesis; Recombinant Fusion Proteins - immunology; RNA; Rodents; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Syntaxin 1; Tissue Distribution; Transcription, Genetic; Vesicular Transport Proteins; Yeasts; Binding protein; Vertebrata; Mammalia; Neuron; Rat; Synaptic transmission; Rodentia; Neurotransmitter; Molecular cloning; Aminoacid sequence; Structural analysis; Brain (vertebrata)
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.91.4.1445

We have identified n-Sec1, a rat brain homolog of the yeast Sec1p protein that participates in the constitutive secretory pathway between the Golgi apparatus and the plasma membrane. The rat brain cDNA is predicted to encode a 68-kDa protein with 65% amino acid identity to Drosophila rop, 59% identity to Caenorhabditis elegans unc-18, and 27% identity to Saccharomyces cerevisiae Sec1p. By RNA blot analysis, n-Sec1 mRNA expression is neural-specific. An anti-peptide antiserum directed against the n-Sec1 carboxyl terminus detects a 68-kDa protein in rat brain cytosol and membranes, but not in peripheral tissues. In the presence of syntaxin 1a, a plasma membrane protein implicated in synaptic vesicle docking, n-Sec1 becomes membrane-associated. n-Sec1 binds to syntaxin 1a, 2, and 3 fusion proteins coupled to agarose beads, but not to syntaxin 4 fusion protein or beads coupled to a variety of other proteins. These findings indicate that n-Sec1 is a neural-specific, syntaxin-binding protein that may participate in the regulation of synaptic vesicle docking and fusion.