| First Author | Melki R | Year | 1996 |
| Journal | Biochemistry | Volume | 35 |
| Issue | 32 | Pages | 10422-35 |
| PubMed ID | 8756698 | Mgi Jnum | J:34803 |
| Mgi Id | MGI:82271 | Doi | 10.1021/bi960788r |
| Citation | Melki R, et al. (1996) Cofactor A is a molecular chaperone required for beta-tubulin folding: functional and structural characterization. Biochemistry 35(32):10422-35 |
| abstractText | Actin and tubulin polypeptide chains acquire their native conformation in the presence of the chaperonin containing TCP-1 (CCT) and, in the case of alpha- and beta-tubulin additional protein cofactors. We recently identified one of these cofactors, termed cofactor A, that is required for the proper folding of the beta-tubulin chain [Gao et al. (1994) J. Cell. Biol. 125, 989-996]. We show here that cofactor A, a monomeric protein that has no measurable affinity for nucleotides, is a highly conserved protein among vertebrates. Its NH2-terminal region is essential for the structural integrity of the protein and consequently for its activity. We demonstrate that cofactor A does not interact with CCT nor does it affect the intrinsic ATPase activity of CCT, alone or in the presence of different target proteins. Thus, unlike GroES, cofactor A does not modulate or coordinate ATP hydrolysis. It does not act as a nucleotide exchange factor or a catalyst in tubulin folding. Rather, we demonstrate that cofactor A participates in the tubulin folding process by interacting with a folding intermediate of beta-tubulin that is released from CCT. Our data imply that cofactor A is a chaperone involved in tubulin folding. |
