title: Primary structure of tektin A1: comparison with intermediate-filament proteins and a model for its association with tubulin.
abstract: Tektins are proteins that form filamentous polymers in the walls of ciliary and flagellar microtubules and that have biochemical and immunological properties similar to those of intermediate-filament proteins. We report here the sequence of a cDNA for tektin A1, one of the main tektins from Strongylocentrotus purpuratus sea urchin embryos. By hybridization analysis, tektin A mRNA appears maximally at ciliogenesis. The predicted structure of tektin A1 (M(r) 52,955) is a series of alpha-helical rod segments separated by nonhelical linkers. The two halves of the rod appear homologous and are probably related by gene duplication. Comparison of tektin A1 with intermediate-filament proteins, including nuclear lamins, reveals a low amino acid homology but similar molecular motif, i.e., pattern of helical and nonhelical domains. This study indicates that tektins are unique proteins but may be evolutionarily related to intermediate-filament proteins, and suggests a structural basis for the interaction of tektins and tubulin in microtubules.
authors.affiliation: Department of Cell Biology and Neuroanatomy, University of Minnesota, Minneapolis 55455.
authors.forename: J M
authors.initials: JM
authors.lastname: Norrander
authors.forename: L A
authors.initials: LA
authors.lastname: Amos
authors.forename: R W
authors.initials: RW
authors.lastname: Linck
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D015870:Gene Expression; D008868:Microtubule Proteins / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D012617:Sea Urchins / Q000196:embryology; D016415:Sequence Alignment; D014404:Tubulin / Q000378:metabolism
chemical_list: D008868:Microtubule Proteins; D012333:RNA, Messenger; D014404:Tubulin; C044103:tektins