The chromosomal passenger complex: guiding Aurora-B through mitosis

Abstract

During mitosis, the chromosomal passenger complex (CPC) orchestrates highly different processes, such as chromosome alignment, histone modification, and cytokinesis. Proper and timely localization of this complex is the key to precise control over the enzymatic core of the CPC, the Aurora-B kinase. We discuss the molecular mechanisms by which the CPC members direct the dynamic localization of the complex throughout cell division. Also, we summarize posttranslational modifications that occur on the CPC and discuss their roles in regulating localization and function of this mitotic complex.

Figure 1.

Interactions within the CPC. Schematic representation of direct interactions between CPC proteins and phosphorylations of Aurora-B within the CPC. Survivin and Borealin interact with the NH₂ terminus of INCENP, whereas Aurora-B binds the COOH-terminal IN-box in INCENP. Mapped Aurora-B phosphorylation sites are indicated.

Figure 2.

Targeting mechanisms of the CPC. For chromatin localization during prometaphase, interaction between HP-1 and INCENP might be required. A multimeric complex of Survivin and Borealin might cooperatively serve as binding interface at the centromere. Within Survivin, the BIR domain is important for centromere targeting, whereas the COOH terminus (C) plays a role in central spindle localization. Putative centromere receptors are Ndc10 and centromeric DNA. At the central spindle during anaphase, Aurora-B interacts with Mklp2 and INCENP has an affinity for microtubules (MTs) regulated by Cdc14. Survivin can also interact with microtubules, but it is unknown whether this contributes to central spindle targeting.