Identification of tubulin deglutamylase among Caenorhabditis elegans and mammalian cytosolic carboxypeptidases (CCPs).
Tubulin polyglutamylation is a reversible post-translational modification, serving important roles in microtubule (MT)-related processes. Polyglutamylases of the tubulin tyrosine ligase-like (TTLL) family add glutamate moieties to specific tubulin glutamate residues, whereas as yet unknown deglutamylases shorten polyglutamate chains. First we investigated regulatory machinery of tubulin glutamylation in MT-based sensory cilia of the roundworm Caenorhabditis elegans. We found that ciliary MTs were polyglutamylated by a process requiring ttll-4. Conversely, loss of ccpp-6 gene function, which encodes one of two cytosolic carboxypeptidases (CCPs), resulted in elevated levels of ciliary MT polyglutamylation. Consistent with a deglutamylase function for ccpp-6, overexpression of this gene in ciliated cells decreased polyglutamylation signals. Similarly, we confirmed that overexpression of murine CCP5, one of two sequence orthologs of nematode ccpp-6, caused a dramatic loss of MT polyglutamylation in cultured mammalian cells. Finally, using an in vitro assay for tubulin glutamylation, we found that recombinantly expressed Myc-tagged CCP5 exhibited deglutamylase biochemical activities. Together, these data from two evolutionarily divergent systems identify C. elegans CCPP-6 and its mammalian ortholog CCP5 as a tubulin deglutamylase.
Kimura
Yoshishige
Y
Department of Molecular Anatomy, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu, Shizuoka 431-3192, Japan.
Kurabe
Nobuya
N
Ikegami
Koji
K
Tsutsumi
Koji
K
Konishi
Yoshiyuki
Y
Kaplan
Oktay Ismail
OI
Kunitomo
Hirofumi
H
Iino
Yuichi
Y
Blacque
Oliver E
OE
Setou
Mitsutoshi
M
D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D002268:Carboxypeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002923:Cilia / Q000378:metabolism; D003600:Cytosol / Q000201:enzymology*; D006801:Humans; D051379:Mice; D008870:Microtubules / Q000378:metabolism; D010453:Peptide Synthases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D017386:Sequence Homology, Amino Acid
D002268:Carboxypeptidases; D010453:Peptide Synthases; C112698:tubulin polyglutamylase