title: A kinase shRNA screen links LATS2 and the pRB tumor suppressor.
abstract: pRB-mediated inhibition of cell proliferation is a complex process that depends on the action of many proteins. However, little is known about the specific pathways that cooperate with the Retinoblastoma protein (pRB) and the variables that influence pRB's ability to arrest tumor cells. Here we describe two shRNA screens that identify kinases that are important for pRB to suppress cell proliferation and pRB-mediated induction of senescence markers. The results reveal an unexpected effect of LATS2, a component of the Hippo pathway, on pRB-induced phenotypes. Partial knockdown of LATS2 strongly suppresses some pRB-induced senescence markers. Further analysis shows that LATS2 cooperates with pRB to promote the silencing of E2F target genes, and that reduced levels of LATS2 lead to defects in the assembly of DREAM (DP, RB [retinoblastoma], E2F, and MuvB) repressor complexes at E2F-regulated promoters. Kinase assays show that LATS2 can phosphorylate DYRK1A, and that it enhances the ability of DYRK1A to phosphorylate the DREAM subunit LIN52. Intriguingly, the LATS2 locus is physically linked with RB1 on 13q, and this region frequently displays loss of heterozygosity in human cancers. Our results reveal a functional connection between the pRB and Hippo tumor suppressor pathways, and suggest that low levels of LATS2 may undermine the ability of pRB to induce a permanent cell cycle arrest in tumor cells.
authors.affiliation: Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, Massachusetts 02129, USA.
authors.forename: Katrin
authors.initials: K
authors.lastname: Tschöp
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Conery
authors.forename: Larisa
authors.initials: L
authors.lastname: Litovchick
authors.forename: James A
authors.initials: JA
authors.lastname: Decaprio
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Settleman
authors.forename: Ed
authors.initials: E
authors.lastname: Harlow
authors.forename: Nicholas
authors.initials: N
authors.lastname: Dyson
mesh_terms: D002453:Cell Cycle / Q000235:genetics / Q000502:physiology; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D047369:Chromatin Immunoprecipitation; D005434:Flow Cytometry; D006801:Humans; D015151:Immunoblotting; D019656:Loss of Heterozygosity / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D011485:Protein Binding / Q000235:genetics / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000502:physiology*; D016160:Retinoblastoma Protein / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*; D000097603:Dyrk Kinases
chemical_list: D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D034741:RNA, Small Interfering; D016160:Retinoblastoma Protein; D025521:Tumor Suppressor Proteins; D000097603:Dyrk Kinases; C406449:LATS2 protein, human