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The AMBRA1 E3 ligase adaptor regulates Cyclin D protein stability [U937 cells]

ABSTRACT: The initiation of cell division is a fundamental process that integrates a large number of intra- and extra-cellular inputs. In mammalian cells, D-type cyclins (Cyclin D) couple these inputs to the decision to initiate DNA replication. Increased levels of Cyclin D promote cell cycle progression by activating cyclin-dependent kinases 4 and 6 (CDK4/6). Accordingly, increased levels and activity of Cyclin D and their associated kinases are strongly linked to unchecked cell proliferation and tumor development. Despite this central role of Cyclin D in cell cycle progression, the mechanisms regulating their levels remain incompletely understood. Here we describe AMBRA1 as the main regulator of Cyclin D protein degradation. We first identify AMBRA1 as the top candidate in a genome-wide CRISPR/Cas9 loss-of-function screen investigating the genetic basis of resistance to chemical CDK4/6 inhibition. AMBRA1 loss results in high protein levels of Cyclin D in cells and in mice. AMBRA1 loss further promotes lung cancer development in a mouse model, and low levels of AMBRA1 correlate with worse survival in lung cancer patients. Mechanistically, AMBRA1 acts as a substrate receptor for the Cullin 4 E3 ligase complex to promote ubiquitylation and proteasomal degradation of the three Cyclin D family members. Thus, AMBRA1 regulates Cyclin D protein levels and contributes to the development of cancer as well as the response of cancer cells to CDK4/6 inhibitors.

ORGANISM(S): Homo sapiens

PROVIDER: GSE146588 | GEO | 2021/02/05

REPOSITORIES: GEO

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The AMBRA1 E3 ligase adaptor regulates Cyclin D protein stability [U2OS cells]

Project description:The initiation of cell division is a fundamental process that integrates a large number of intra- and extra-cellular inputs. In mammalian cells, D-type cyclins (Cyclin D) couple these inputs to the decision to initiate DNA replication. Increased levels of Cyclin D promote cell cycle progression by activating cyclin-dependent kinases 4 and 6 (CDK4/6). Accordingly, increased levels and activity of Cyclin D and their associated kinases are strongly linked to unchecked cell proliferation and tumor development. Despite this central role of Cyclin D in cell cycle progression, the mechanisms regulating their levels remain incompletely understood. Here we describe AMBRA1 as the main regulator of Cyclin D protein degradation. We first identify AMBRA1 as the top candidate in a genome-wide CRISPR/Cas9 loss-of-function screen investigating the genetic basis of resistance to chemical CDK4/6 inhibition. AMBRA1 loss results in high protein levels of Cyclin D in cells and in mice. AMBRA1 loss further promotes lung cancer development in a mouse model, and low levels of AMBRA1 correlate with worse survival in lung cancer patients. Mechanistically, AMBRA1 acts as a substrate receptor for the Cullin 4 E3 ligase complex to promote ubiquitylation and proteasomal degradation of the three Cyclin D family members. Thus, AMBRA1 regulates Cyclin D protein levels and contributes to the development of cancer as well as the response of cancer cells to CDK4/6 inhibitors.

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The AMBRA1 E3 ligase adaptor regulates Cyclin D protein stability

Project description:The AMBRA1 E3 ligase adaptor regulates Cyclin D protein stability

| PRJNA670881 | ENA

Quantitative proteomics of AMBRA1

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