serine/threonine protein kinase PLK4; polo-like kinase 4; PLK-4; serine/threonine protein kinase 18; serine/threonine protein kinase Sak (PLK4 SAK STK18)

Function

• serine/threonine protein kinase
• role in centriole duplication
• able to trigger procentriole formation on the surface of the parental centriole cylinder, leading to the recruitment of centriole biogenesis proteins such as SASS6, CENPJ/CPAP, CP110, CEP135 & gamma-tubulin
• when overexpressed, PLK4 is able to induce centrosome amplification through the simultaneous generation of multiple procentrioles adjoining each parental centriole during S phase
• role in trophoblast differentiation by phosphorylating HAND1, leading to disrupt the interaction between HAND1 & MDFIC & activate HAND1
• phosphorylates CDC25C & CHEK2/CHK2
• ubiquitinated, leading to its degradation by the proteasome
• Tyr-phosphorylated by TEC
• interacts with CEP152 (via N-terminus)

Structure

• homodimer (putative)
• belongs to the protein kinase superfamily, Ser/Thr protein kinase family, CDC5/polo subfamily
• contains 1 POLO box domain
• contains 1 protein kinase domain

Compartment

• cytoplasm, cytoskeleton, centrosome, centriole
• nucleus, nucleolus (putative)
• cleavage furrow
• associates with centrioles throughout the cell cycle
• not present at cleavage furrows

Alternative splicing

named isoforms=3

Expression

• down-regulated in HCT116 colorectal cancer cells, leading to aberrant centrioles composed of disorganized cylindrical microtubules & displaced appendages
• down-regulated by p53/TP53

Pathology

• PLK4 role in tumorigenesis suggested by its role in centriole replication

More general terms

• serine/threonine kinase

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=10733
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:10733
• OMIM: https://mirror.omim.org/entry/605031
• UniProt: http://www.uniprot.org/uniprot/O00444.html