Axonemal tubulin polyglycylation probed with two monoclonal antibodies: widespread evolutionary distribution, appearance during spermatozoan maturation and possible function in motility

Abstract

Two monoclonal antibodies, AXO 49 and TAP 952, probed with carboxy-terminal peptides from Paramecium axonemal tubulin and with polyglycylated synthetic peptides, are found to recognize differently tubulin polyglycylation, the most recently identified posttranslational modification discovered in Paramecium axonemal tubulin. With these antibodies, we show that tubulin polyglycylation is widely distributed in organisms ranging from ciliated protozoa to mammals; it arose early in the course of evolution, but seems to be absent in primitive protozoa such as the Euglenozoa. Tubulin polyglycylation is the last posttranslational modification which takes place in the course of Drosophila spermatogenesis and its occurrence corresponds to the end of spermatozoan maturation. An involvement of polyglycylated tubulin in axoneme motility is suggested since AXO 49 and TAP 952 specifically inhibit the reactivated motility of sea urchin spermatozoa.