title: Association of betaine-homocysteine S-methyltransferase with microtubules.
abstract: In mammals, betaine of the mitochondrial matrix is used in the cytosol by betaine-homocysteine S-methyltransferase for methionine synthesis. The resulting dimethylglycine is shuttled back into the mitochondrial matrix for further degradation. Nanospray tandem mass spectrometry and N-terminal amino acid sequencing of microtubule-associated proteins from rat liver tubulin revealed that betaine-homocysteine S-methyltransferase is microtubule associated. This was confirmed by confocal laser scanning microscopy of HepG2 cells labeled with betaine-homocysteine S-methyltransferase- and alpha-tubulin-specific monoclonal antibodies. The association of betaine-homocysteine S-methyltransferase with the cytoskeleton may functionally integrate the mitochondrial and cytoplasmic compartments of choline degradation.
authors.affiliation: Institut für Biochemie und Molekularbiologie, Universität Freiburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Sandu
authors.forename: P
authors.initials: P
authors.lastname: Nick
authors.forename: D
authors.initials: D
authors.lastname: Hess
authors.forename: E
authors.initials: E
authors.lastname: Schiltz
authors.forename: T A
authors.initials: TA
authors.lastname: Garrow
authors.forename: R
authors.initials: R
authors.lastname: Brandsch
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D005455:Fluorescent Antibody Technique; D050904:Homocysteine S-Methyltransferase; D008099:Liver / Q000201:enzymology; D008780:Methyltransferases / Q000737:chemistry / Q000378:metabolism*; D008870:Microtubules / Q000201:enzymology*; D051381:Rats
chemical_list: D008780:Methyltransferases; D050904:Homocysteine S-Methyltransferase