Solution structure of the Tctex1 dimer reveals a mechanism for dynein-cargo interactions.
Tctex1 is a light chain found in both cytoplasmic and flagellar dyneins and is involved in many fundamental cellular activities, including rhodopsin transport within photoreceptors, and may function in the non-Mendelian transmission of t haplotypes in mice. Here, we present the NMR solution structure for the Tctex1 dimer from Chlamydomonas axonemal inner dynein arm I1. Structural comparisons reveal a strong similarity with the LC8 dynein light chain dimer, including formation of a strand-switched beta sheet interface. Analysis of the Tctex1 structure enables the dynein intermediate chain binding site to be identified and suggests a mechanism by which cargo proteins might be attached to this microtubule motor complex. Comparison with the alternate dynein light chain rp3 reveals how the specificity of dynein-cargo interactions mediated by these dynein components is achieved. In addition, this structure provides insight into the consequences of the mutations found in the t haplotype forms of this protein.
Wu
Hongwei
H
Department of Molecular, Microbial, and Structural Biology, 263 Farmington Avenue, Farmington, Connecticut 06030, USA.
Maciejewski
Mark W
MW
Takebe
Sachiko
S
King
Stephen M
SM
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002696:Chlamydomonas / Q000378:metabolism*; D019281:Dimerization; D004398:Dyneins / Q000378:metabolism*; D006239:Haplotypes; D006801:Humans; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000737:chemistry* / Q000235:genetics; D017433:Protein Structure, Secondary; D021381:Protein Transport; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics; D012996:Solutions; D040681:Structural Homology, Protein; D056427:t-Complex Genome Region
C533386:Dynlt1b protein, mouse; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D015800:Protozoan Proteins; D012996:Solutions; D004398:Dyneins