Beta-tubulin folding is modulated by the isotype-specific carboxy-terminal domain.
To investigate the contribution of the carboxy-terminal domain in the process of tubulin folding and dimer formation, we constructed a beta 1-beta 3 tubulin chimaera and two truncated carboxy-terminal beta 3-tubulins. The capacity of these altered polypeptides to incorporate into dimers and into microtubules was tested by non-denaturing electrophoresis and co-assembly experiments. The chimaera and the truncated protein with a deletion encompassing the last 12 amino acid residues (beta 3 delta C12) were incorporated into dimers and microtubules, though the level of incorporation was diminished compared to wild-type beta 3-tubulin. However, the level of incorporation of beta 3 delta C12 into subtilisin-digested dimers was similar to the incorporation of wild-type beta 3-tubulin. Since subtilisin deletes the carboxy-terminal region, these results suggest a regulatory role of the carboxy-terminal region in the folding process itself and not in the formation of the dimer.
Fontalba
A
A
Departamento de Biologia Molecular, Facultad de Medicina, Universidad de Cantabria, Spain.
Avila
J
J
Zabala
J C
JC
D000818:Animals; D001704:Biopolymers / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D066298:In Vitro Techniques; D051379:Mice; D016297:Mutagenesis, Site-Directed; D017510:Protein Folding; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014404:Tubulin / Q000737:chemistry / Q000378:metabolism*
D001704:Biopolymers; D011993:Recombinant Fusion Proteins; D014404:Tubulin