Martin Flavin

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A posttranslational modification of tubulin with potential significance for the regulation of microtubule assembly or function has been revealed by the discovery of an enzyme (tubulin--tyrosine ligase) which can add a tyrosine residue to the alphachain, apparently through peptide bond linkage to a C-terminal glutamate or glutamine. The ability to add(More)
Glucocorticoid hormones were found to regulate DNA demethylation within a key enhancer of the rat liver-specific tyrosine aminotransferase (Tat) gene. Genomic footprinting analysis shows that the glucocorticoid receptor uses local DNA demethylation as one of several steps to recruit transcription factors in hepatoma cells. Demethylation occurs within 2-3(More)
A carboxypeptidase purified from brain catalyzes the release of COOH-terminal tyrosine without further digesting tubulin. It is distinct from previously described carboxypeptidases, and appears to have specificity for tubulin as it is not inhibited by peptides and proteins with COOH-terminal tyrosine, and because, unlike carboxypeptidase A (which by(More)
A microtubule-associated protein (the 270-kDa MAP-2) was prepared in two defined states of phosphorylation by (a) phosphorylation by associated kinase to the extent of 11-14 mol/mol, and (b) removal of 70-80% of this phosphate with a protein phosphatase purified from brain. The newly introduced phosphate was in addition to about 10 mol/mol already present(More)
Nucleotides have at least two functions in eukaryotic cilia and flagella. ATP, originating in the cells, is utilized for motility by energy-transducing protein(s) called dynein, and the binding of guanine nucleotides to tubulin, and probably certain transformations of the bound nucleotides, are prerequisites for the assembly of microtubules. Besides dynein,(More)
Microtubule-associated protein 2 (MAP-2) purified after microtubule assembly cycles from bovine brain had been shown to contain about 10 esterified phosphates (mol/mol), which were relatively phosphatase resistant and essentially confined to the projection domain which contributes to the visible arms on microtubules. The kinase responsible for(More)
A post-translational modification of tubulin with potential regulatory significance has been revealed by the discovery of an enzyme (tubulin-tyrosine ligase) in brain extracts which can add a tyrosine residue to the alpha chain, apparently through peptide bond linkage to a C-terminal glutamate. We have investigated whether this modification also occurs in(More)