Characterisation of PGs1, a subunit of a protein complex co-purifying with tubulin polyglutamylase.
Polyglutamylation is a post-translational modification initially discovered on tubulin. It has been implicated in multiple microtubule functions, including neuronal differentiation, axonemal beating and stability of the centrioles, and shown to modulate the interaction between tubulin and microtubule associated proteins. The enzymes catalysing this modification are not yet known. Starting with a partially purified fraction of mouse brain tubulin polyglutamylase, monoclonal antibodies were raised and used to further purify the enzyme by immunoprecipitation. The purified enzyme complex (Mr 360x103) displayed at least three major polypeptides of 32, 50 and 80x103, present in stochiometric amounts. We show that the 32x103 subunit is encoded by the mouse gene GTRGEO22, the mutation of which has recently been implicated in multiple defects in mice, including male sterility. We demonstrate that this subunit, called PGs1, has no catalytic activity on its own, but is implicated in the localisation of the enzyme at major sites of polyglutamylation, i.e. neurones, axonemes and centrioles.
Regnard
Catherine
C
Centre de Recherches de Biochimie Macromoléculaire, CNRS, 34293 Montpellier, France.
Fesquet
Didier
D
Janke
Carsten
C
Boucher
Dominique
D
Desbruyéres
Elisabeth
E
Koulakoff
Annette
A
Insina
Christine
C
Travo
Pierre
P
Eddé
Bernard
B
D000818:Animals; D002478:Cells, Cultured; D002502:Centrioles / Q000378:metabolism*; D051379:Mice; D008870:Microtubules / Q000378:metabolism*; D009474:Neurons; D010453:Peptide Synthases; D011099:Polyglutamic Acid / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014404:Tubulin / Q000378:metabolism*
D021122:Protein Subunits; D014404:Tubulin; D011099:Polyglutamic Acid; D010453:Peptide Synthases; C112698:tubulin polyglutamylase