LZAP is a novel Wip1 binding partner and positive regulator of its phosphatase activity <i>in vitro</i>

Chemotherapy and radiation, the two most common cancer therapies, exert their anticancer effects by causing damage to cellular DNA. However, systemic treatment damages DNA not only in cancer, but also in healthy cells, resulting in the progression of serious side effects and limiting efficacy of the treatment. Interestingly, in response to DNA damage, p53 seems to play an opposite role in normal and in the majority of cancer cells—wild-type p53 mediates apoptosis in healthy tissues, attributing to the side effects, whereas mutant p53 often is responsible for acquired cancer resistance to the treatment. Here, we show that leucine zipper-containing ARF-binding protein (LZAP) binds and stabilizes p53. LZAP depletion eliminates p53 protein independently of its mutation status, subsequently protecting wild-type p53 cells from DNA damage-induced cell death, while rendering cells expressing mutant p53 more sensitive to the treatment. In human non-small-cell lung cancer, LZAP levels correlated with p53 levels, suggesting that loss of LZAP may represent a novel mechanism of p53 inactivation in human cancer. Our studies establish LZAP as a p53 regulator and p53-dependent determinative of cell fate in response to DNA damaging treatment.

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“…GST was from Abcam (Cambridge, MA, USA). Recombinant LZAP was purified from Escherichia coli BL21(DE3) as described in Wamsley et al 35 …”

Section: Methodsmentioning

confidence: 99%

Loss of LZAP inactivates p53 and regulates sensitivity of cells to DNA damage in a p53-dependent manner

et al. 2017

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“…CDK5RAP3, also known as LZAP and C53, was first identified as a binding protein of cyclindependent kinase 5 (CDK5) activator (Ching et al, 2000). Subsequent research showed that CDK5RAP3 interacts with a range of proteins, including RelA (Wang et al, 2007), ARF (Wang et al, 2006), Chk1 (Jiang et al, 2005), Chk2 (Jiang et al, 2005), PAK4 (Mak et al, 2011), Wip1 (Wamsley et al, 2017), γ-tubulin (Horější et al, 2012) and p38 MAPK (An et al, 2011). By interacting with these proteins, CDK5RAP3 exerts the role in regulating the cell cycle, cell survival, cell adherence/invasion, tumorigenesis and metastasis (Jiang et al, 2005;Jiang et al, 2009;Liu et al, 2011;Wang et al, 2007Wang et al, , 2006Zhao et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

CDK5RAP3, a UFL1 substrate adaptor, is critical for liver development

et al. 2019

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Protein modification by ubiquitin and ubiquitin-like proteins (UBLs) regulates numerous biological functions. The UFM1 system, a novel UBL conjugation system, is implicated in mouse development and hematopoiesis. However, its broad biological functions and working mechanisms remain largely elusive. CDK5RAP3, a possible ufmylation substrate, is essential for epiboly and gastrulation in zebrafish. Herein, we report a crucial role of CDK5RAP3 in liver development and hepatic functions. Cdk5rap3 knockout mice displayed prenatal lethality with severe liver hypoplasia, as characterized by delayed proliferation and compromised differentiation. Hepatocyte-specific Cdk5rap3 knockout mice suffered post-weaning lethality, owing to serious hypoglycemia and impaired lipid metabolism. Depletion of CDK5RAP3 triggered endoplasmic reticulum stress and activated unfolded protein responses in hepatocytes. We detected the in vivo interaction of CDK5RAP3 with UFL1, the defined E3 ligase in ufmylation. Notably, loss of CDK5RAP3 altered the ufmylation profile in liver cells, suggesting that CDK5RAP3 serves as a novel substrate adaptor for this UBL modification. Collectively, our study identifies CDK5RAP3 as an important regulator of ufmylation and suggests the involvement of ufmylation in mammalian development.

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“…Likewise, plant PP2Cs are not known to be restricted to specific dephosphorylation motifs and thus are not likely to have the same level of inherent substrate specificity as kinases. However, we are not aware of any systematic analysis to investigate the dephosphorylation specificity of plant PP2Cs, and some mammalian PP2Cs, such as wild type p53‐induced protein 1 (WIP1), are thought to prefer certain types of dephosphorylation sites (see, e.g., Wamsley et al, ).…”

Section: Introductionmentioning

confidence: 99%

The flip side of phospho‐signalling: Regulation of protein dephosphorylation and the protein phosphatase 2Cs

Bhaskara

Wong

Verslues

2019

Plant Cell & Environment

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Protein phosphorylation is a key signalling mechanism and has myriad effects on protein function. Phosphorylation by protein kinases can be reversed by protein phosphatases, thus allowing dynamic control of protein phosphorylation. Although this may suggest a straightforward kinase-phosphatase relationship, plant genomes contain five times more kinases than phosphatases. Here, we examine phospho-signalling from a protein phosphatase centred perspective and ask how relatively few phosphatases regulate many phosphorylation sites. The most abundant class of plant phosphatases, the protein phosphatase 2Cs (PP2Cs), is surrounded by a web of regulation including inhibitor and activator proteins as well as posttranslational modifications that regulate phosphatase activity, control phosphatase stability, or determine the subcellular locations where the phosphatase is present and active. These mechanisms are best established for the Clade A PP2Cs, which are key components of stress and abscisic acid signalling.We also describe other PP2C clades and illustrate how these phosphatases are highly regulated and involved in a wide range of physiological functions. Together, these examples of multiple layers of phosphatase regulation help explain the unbalanced kinase-phosphatase ratio. Continued use of phosphoproteomics to examine phosphatase targets and phosphatase-kinase relationships will be important for deeper understanding of phosphoproteome regulation.

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LZAP is a novel Wip1 binding partner and positive regulator of its phosphatase activity in vitro

Cited by 14 publications

References 63 publications

Loss of LZAP inactivates p53 and regulates sensitivity of cells to DNA damage in a p53-dependent manner

Loss of LZAP inactivates p53 and regulates sensitivity of cells to DNA damage in a p53-dependent manner

CDK5RAP3, a UFL1 substrate adaptor, is critical for liver development

The flip side of phospho‐signalling: Regulation of protein dephosphorylation and the protein phosphatase 2Cs

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