@article{b7a858ebdae04710bbaf5710076c9006,
title = "Rb-dependent cellular senescence, multinucleation and susceptibility to oncogenic transformation through PKC scaffolding by SSeCKS/AKAP12",
abstract = "A subset of AKAPs (A Kinase Anchoring Proteins) regulate signaling and cytoskeletal pathways through the spaciotemporal scaffolding of multiple protein kinases (PK), such as PKC and PKA, and associations with the plasma membrane and the actin-based cytoskeleton. SSeCKS/Gravin/Akap12 expression is severely downregulated in many advanced cancers and exhibits tumor- and metastasis-suppressing activity. akap12-null (KO) mice develop prostatic hyperplasia with focal dysplasia, but the precise mechanism how Akap12 prevents oncogenic progression remains unclear. Here, we show that KO mouse embryonic fibroblasts (MEF) exhibit premature senescence marked by polyploidy and multinucleation, and by increased susceptibility to oncogenic transformation. Although p53 and Rb pathways are activated in the absence of Akap12, senescence is dependent on Rb. Senescence is driven by the activation of PKCα, which induces p16Ink4a/Rb through a MEK-dependent downregulation of Id1, and PKCδ, which downregulates Lats1/Warts, a mitotic exit network kinase required for cytokinesis. Our data strongly suggest that Akap12 controls Rb-mediated cell aging and oncogenic progression by directly scaffolding and attenuating PKCα/δ.",
keywords = "Binucleation, Id1, Lats1/Warts, MEF, PKC, Polyploidy, Rb, SSeCKS/Akap12, Senescence",
author = "Shin Akakura and Peter Nochajski and Lingqiu Gao and Paula Sotomayor and Matsui, {Sei Ichi} and Gelman, {Irwin H.}",
note = "Funding Information: malin for 1 min, and incubated in SAβgal soIndustries), and 4 mm frozen sections were cu%lutit, fiPon (xed iOpH 6n 1P.% fU0) at oEr-JTfoanUr dd tSiJscecCushnVsinicaUg ul aFnpublished work, Eiji Hara for PKC plasmids, dvice, Philip W. Hinds and Marcelo Kazanietz 37°C for 16 h, followed by eosin counterstaining. The tissues Kaoru Hazeki for PKCδ-shRNA plasmids, Janet Morgan for were imaged using an Olympus BX45 microscope (Olympus) reagents, David Goodrich for critical reading of the manu-equipped with a DP25 camera (Olympus), and data were ana-script and Mary Vaughan for expert IHC services. This work lyzed using DP2-BSW software. was supported by CA94108 and DOD Prostate Cancer Awards Semi-quantitative (semi-Q) RT-PCR. Total RNA was pre-W81XWH-08-1-0026 and W81XWH-07-1-0184 (I.H.G.), and pared by standard TRIZOL-based methods (according to the in part, by the NCI Cancer Center Support Grant to the Roswell manufacturer{\textquoteright}s specifications). Reverse transcription was per-Park Cancer Institute (CA016056). formed according to the manufacturer{\textquoteright}s instructions (Fermentas). PCR reactions were performed using Taq DNA polymerase (New England Biolabs) using the following parameters: hotstart, fol- lowed by 25–30 cycles of 95°C (30 s), 55°C (30 s) and 72°C (45 s). PCR products were resolved on agarose gels followed by ethidium bromide staining. The primer sequences are described in Table 1.",
year = "2010",
month = dec,
day = "1",
doi = "10.4161/cc.9.23.13974",
language = "English",
volume = "9",
pages = "4656--4665",
journal = "Cell Cycle",
issn = "1538-4101",
publisher = "Taylor and Francis Ltd.",
number = "23",
}