Polo-like kinases: conservation and divergence in their functions and regulation

Abstract

Polo-like kinases (Plks) are potent regulators of M phase that are conserved from yeasts to humans. Their roles in mitotic entry, spindle pole functions and cytokinesis are broadly conserved despite physical and molecular differences in these processes in disparate organisms. Plks are characterized by their Polo-box domain, which mediates protein interactions. They are additionally controlled by phosphorylation, proteolysis and transcription, depending on the biological context. Plks are now recognized to link cell division to developmental processes and to function in differentiated cells. A comparison of Plk function and regulation between organisms offers insight into the rich variations of cell division.

Cytokinesis microtubule organisers at a glance

“…The first class includes the core microtubule organisers, such as protein regulator of cytokinesis 1 (PRC1) and centralspindlin. The second category is made up of their upstream regulators, represented by mitotic kinases, such as Aurora B kinase, which is a component of the chromosomal passenger complex (CPC) (Ruchaud et al, 2007), and polo-like kinase 1 (PLK1) (Archambault and Glover, 2009). The third class comprises the downstream effectors, including epithelial cell-transforming sequence 2 oncogene (ECT2), which is the major activator of Rho GTPase, and centrosomal protein of 55 kDa (CEP55), which is a key to recruitment of abscission factors to the midbody.…”

Cloning, expression and purification of functionally active Saccharomyces cerevisiae Polo-like Kinase, Cdc5 in E. coli

“…PLKs are central regulators of cell cycle, and control multiple mitotic events [1]. The conserved mitotic functions of PLK in all eukaryotes include entry into M phase, progression through mitosis, metaphase to anaphase transition, exit from mitosis and cytokinesis [1].…”

“…PLKs are central regulators of cell cycle, and control multiple mitotic events [1]. The conserved mitotic functions of PLK in all eukaryotes include entry into M phase, progression through mitosis, metaphase to anaphase transition, exit from mitosis and cytokinesis [1]. PLK belongs to Ser/Thr subfamily of protein kinases, characterized by kinase domain (KD) at the N-terminus and a conserved signature motif called polo-box domain (PBD) at C-terminus [2,3].…”

“…Mutations in the polo gene result in abnormal mitotic and meiotic divisions, indicating PLK's vital role in cell cycle [1,4]. After the discovery of polo, PLKs have been subsequently identified in other eukaryotes, except plants [1,4].…”

“…Mutations in the polo gene result in abnormal mitotic and meiotic divisions, indicating PLK's vital role in cell cycle [1,4]. After the discovery of polo, PLKs have been subsequently identified in other eukaryotes, except plants [1,4]. Whereas mammals have multiple PLKs (Plk1, Plk2, Plk3, and Plk4) [2,3], the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe have only one PLK (Cdc5 in budding yeast [5] and Plo1 in fission yeast [6].…”