Conserved beta-tubulin binding domain for the microtubule-associated motors underlying sperm motility and fast axonal transport.
An antiserum against tubulin, NS20, has been previously shown to inhibit anterograde and retrograde axonal transport by 50% in vivo and in vitro. We report here that Protein A purified NS20 antibodies also attenuate sperm motility by 50% in demembranated sea urchin sperm. This inhibition is absorbed out by preincubating the NS20 antibodies with a biochemically purified porcine microtubule preparation, with recombinant Trypanosoma beta- (but not alpha-) tubulin and most specifically, with a 37 amino acid (a.a.) synthetic peptide corresponding to a domain near (but not including) the porcine beta-tubulin C terminus. Furthermore, addition of this beta-tubulin peptide alone is sufficient to attenuate motility by 50% in demembranated sperm, indicating that this critical 37a.a. NS20 antigen is a motor binding domain. Together, the results suggest that at least two phenotypically distinct forms of microtubule-based motility, axonal transport and flagellar beating, are homologous at the fundamental level of the microtubule domains (the beta-tubulin peptide and we suggest a distinct but similarly located alpha-tubulin domain) mediating the attachment of tubulin-associated motors.
Goldsmith
M
M
Department of Anatomy, University of Toronto, Canada.
Connolly
J A
JA
Kumar
N
N
Wu
J
J
Yarbrough
L R
LR
van der Kooy
D
D
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology; D001370:Axonal Transport; D001665:Binding Sites; D000939:Epitopes / Q000276:immunology; D008297:Male; D008870:Microtubules / Q000378:metabolism*; D008969:Molecular Sequence Data; D010641:Phenotype; D011994:Recombinant Proteins / Q000378:metabolism; D012617:Sea Urchins; D013045:Species Specificity; D013081:Sperm Motility; D013082:Sperm Tail / Q000502:physiology; D013552:Swine; D014404:Tubulin / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
D000906:Antibodies; D000939:Epitopes; D011994:Recombinant Proteins; D014404:Tubulin