title: The pallid gene encodes a novel, syntaxin 13-interacting protein involved in platelet storage pool deficiency.
abstract: Pallid (pa) is 1 of 13 platelet storage pool deficiency (SPD) mouse mutants. pa animals suffer from prolonged bleeding time, pigment dilution, kidney lysosomal enzyme elevation, serum alpha1-antitrypsin activity deficiency and abnormal otolith formation. As with other mouse mutants of this class, characterization of pa mice suggests a defect in organelle biosynthesis. Here we describe the physical mapping, positional cloning, and mutational and functional analysis of the gene that is defective in pa mice. It encodes a ubiquitously expressed, highly charged 172-amino-acid protein (termed pallidin) with no homology to known proteins. We detected a nonsense mutation at codon 69 of this gene in the pallid mutant. In a yeast two-hybrid screen, we discovered that pallidin interacts with syntaxin 13, a t-SNARE protein that mediates vesicle-docking and fusion. We confirmed this interaction by co-immunoprecipitation assay. Immunofluorescence studies corroborate that the cellular distribution of pallidin overlaps that of syntaxin 13. Whereas the mocha and pearl SPD mutants have defects in Ap-3, our findings suggest that pa SPD mutants are defective in a more downstream event of vesicle-trafficking: namely, vesicle-docking and fusion.
authors.affiliation: Howard Hughes Medical Institute and Department of Medicine, University of California, San Francisco, California 94143-0794, USA.
authors.forename: L
authors.initials: L
authors.lastname: Huang
authors.forename: Y M
authors.initials: YM
authors.lastname: Kuo
authors.forename: J
authors.initials: J
authors.lastname: Gitschier
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002874:Chromosome Mapping; D002875:Chromosomes / Q000235:genetics; D003001:Cloning, Molecular; D005455:Fluorescent Antibody Technique; D007425:Intracellular Membranes / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D037102:Lectins; D008561:Membrane Fusion; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D008969:Molecular Sequence Data; D009154:Mutation; D016366:Open Reading Frames / Q000235:genetics; D010981:Platelet Storage Pool Deficiency / Q000235:genetics* / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D050765:Qa-SNARE Proteins; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D020798:Two-Hybrid System Techniques
chemical_list: C400284:BLOC1S6 protein, human; C513476:Bloc1s6 protein, mouse; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D037102:Lectins; D008565:Membrane Proteins; D050765:Qa-SNARE Proteins; D012333:RNA, Messenger