Sequences within the conserved cyclin box of human cyclin A are sufficient for binding to and activation of cdc2 kinase.

AUTOR(ES)

Lees, E M

RESUMO

Cyclins are pivotal in the coordinate regulation of the cell cycle. By physical association, they are able to activate at least one of the cyclin-dependent kinases, cdc2. How this association between the catalytic moiety and cyclins leads to subsequent activation of the kinase remains unclear. In this report, we describe experiments to investigate this event at a physical level. Our approach was to map the regions required on the cyclin A molecule for interaction with cdc2. We have mapped the contact regions to two small noncontiguous stretches of amino acids, residues 189 to 241 and 275 to 320, both located within the conserved cyclin box domain of the protein. We have further shown that this region not only represents a contact site for cdc2 but apparently represents an intact functional domain with respect to cdc2 activation. This region alone is sufficient to stimulate maturation when injected into immature Xenopus laevis oocytes. This observation implies that events leading to the activation of cdc2 kinase can be mediated through small regions of the cyclin molecule that are located in the cyclin box. These regions contain some of the most highly conserved residues found between all the cyclin members so far identified. This suggests that the cyclin family members may have conserved a similar mechanism to bind and activate cyclin-dependent kinases.

Documentos Relacionados

• A minimal cascade model for the mitotic oscillator involving cyclin and cdc2 kinase.
• The retinoblastoma protein physically associates with the human cdc2 kinase.
• Structure and developmental expression of the chicken CDC2 kinase.
• Disassembly of in vitro formed lamin head-to-tail polymers by CDC2 kinase.
• A three-dimensional model of the Cdc2 protein kinase: localization of cyclin- and Suc1-binding regions and phosphorylation sites.