Accumulation of delta 2-tubulin, a major tubulin variant that cannot be tyrosinated, in neuronal tissues and in stable microtubule assemblies.
Tubulin is the major protein component of brain tissue. It normally undergoes a cycle of tyrosination-detyrosination on the carboxy terminus of its alpha-subunit and this results in subpopulations of tyrosinated tubulin and detyrosinated tubulin. Brain tubulin preparations also contain a third major tubulin subpopulation, composed of a non-tyrosinatable variant of tubulin that lacks a carboxy-terminal glutamyl-tyrosine group on its alpha-subunit (delta 2-tubulin). Here, the abundance of delta 2-tubulin in brain tissues, its distribution in developing rat cerebellum and in a variety of cell types have been examined and compared with that of total alpha-tubulin and of tyrosinated and detyrosinated tubulin. Delta 2-tubulin accounts for approximately 35% of brain tubulin. In rat cerebellum, delta 2-tubulin appears early during neuronal differentiation and is detected only in neuronal cells. This apparent neuronal specificity of delta 2-tubulin is confirmed by examination of its distribution in cerebellar cells in primary cultures. In such cultures, neuronal cells are brightly stained with anti-delta 2-tubulin antibody while glial cells are not. Delta 2-tubulin is apparently present in neuronal growth cones. As delta 2-tubulin, detyrosinated tubulin is enriched in neuronal cells, but in contrast with delta 2-tubulin, detyrosinated tubulin is not detectable in Purkinje cells and is apparently excluded from neuronal growth cones. In a variety of cell types such as cultured fibroblasts of primary culture of bovine adrenal cortical cells, delta 2-tubulin is confined to very stable structures such as centrosomes and primary cilia. Treatment of such cells with high doses of taxol leads to the appearance of delta 2-tubulin in microtubule bundles. Delta 2-tubulin also occurs in the paracrystalline bundles of protofilamentous tubulin formed after vinblastine treatment. Delta 2-tubulin is present in sea urchin sperm flagella and it appears in sea urchin embryo cilia during development. Thus, delta 2-tubulin is apparently a marker of very long-lived microtubules. It might represent the final stage of alpha-tubulin maturation in long-lived polymers.
Paturle-Lafanechère
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L
INSERM Unité 366, Laboratoire du Cytosquelette, Centre d'Etudes Nucléaires de Grenoble, France.
Manier
M
M
Trigault
N
N
Pirollet
F
F
Mazarguil
H
H
Job
D
D
D016475:3T3 Cells / Q000737:chemistry / Q000648:ultrastructure; D000302:Adrenal Cortex / Q000166:cytology / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D018385:Centrosome / Q000737:chemistry / Q000648:ultrastructure; D002531:Cerebellum / Q000196:embryology / Q000378:metabolism; D002923:Cilia / Q000737:chemistry / Q000648:ultrastructure; D005407:Flagella / Q000737:chemistry / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D006367:HeLa Cells / Q000737:chemistry / Q000648:ultrastructure; D006801:Humans; D008297:Male; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000032:analysis; D008870:Microtubules / Q000737:chemistry* / Q000187:drug effects; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics; D009474:Neurons / Q000378:metabolism* / Q000648:ultrastructure; D017239:Paclitaxel / Q000494:pharmacology; D011499:Protein Processing, Post-Translational; D011689:Purkinje Cells / Q000378:metabolism; D051381:Rats; D012617:Sea Urchins / Q000737:chemistry / Q000196:embryology; D014404:Tubulin / Q000096:biosynthesis* / Q000235:genetics; D014443:Tyrosine / Q000378:metabolism
D005904:Glial Fibrillary Acidic Protein; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D014404:Tubulin; D014443:Tyrosine; D017239:Paclitaxel