Src-family tyrosine kinase fyn phosphorylates phosphatidylinositol 3-kinase enhancer-activating Akt, preventing its apoptotic cleavage and promoting cell survival

Tang, Xiaoling; Feng, Yue; Ye, K

doi:10.1038/sj.cdd.4402011

Cited by 48 publications

(47 citation statements)

References 30 publications

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“…Noticeably, compared to FynD cells, PIKE-L apoptotic cleavage is partially decreased in FynA cells (Supplemental Figure 1C, right lower panel), an effect similar to netrin-1-treated cells. PIKE-A is mainly phosphorylated by Fyn on Y681 and Y774 residues 14 , which correspond to Y1032 and Y1124 in PIKE-L. Immunoprecipitation assay reveals that wild-type PIKE-L strongly interacts with UNC5B, whereas Y1032F, Y1124F and Y1032, 1124F mutants fail to interact with UNC5B. As expected, PIKE-L wild-type is evidently tyrosine phosphorylated, which is abolished in PIKE-L mutants ( Figure 3A, top and 2 nd panels).…”

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confidence: 67%

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Netrin-1 mediates neuronal survival through PIKE-L interaction with the dependence receptor UNC5B

et al. 2008

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Netrins, a family of secreted molecules, play critical roles in axon guidance and cell migration during neuronal development 1,2. In addition to its role as a chemotropic molecule, netrin-1 also acts as a survival factor 3-7 . Both UNC5 (i.e. UNC5A, B, C or D) and DCC are transmembrane receptors for netrin-1 8 ,9. In the absence of netrin-1, DCC and UNC5 act as dependence receptors and trigger apoptosis 3,6, 10 . However, how netrin-1 suppresses the apoptotic activity of the receptors remains elusive. Here, we show that netrin-1 induces interaction of UNC5B with the brain specific GTPase PIKE-L. This interaction triggers activation of PI 3-kinase signaling, prevents UNC5B's proapoptotic activity and enhances neuronal survival. Moreover, this process tightly relies on Fyn as PIKE-L is tyrosine phosphorylated in response to netrin-1 and the netrin-1-mediated interaction of UNC5B with PIKE-L is inhibited in Fyn null mice. Thus, PIKE-L acts as a downstream survival effector for netrin-1 through UNC5B in the nervous system. PIKE-L is a brain specific GTPase, which binds and stimulates PI 3-kinase in a GTP-dependent manner 11, 12 . PIKE-L binds Homer, an adaptor protein for metabotropic glutamate receptor (mGluR). Activation of mGluRIs enhances formation of an mGluRI-Homer-PIKE-L complex, leading to activation of PI 3-kinase and prevention of neuronal apoptosis 13 . PIKE is also a substrate for caspases. PIKE can be phosphorylated on tyrosine residues by Fyn, leading to its resistance to caspase cleavage 14. To search for PIKE-L-binding proteins, we conducted yeast two-hybrid screening using GTPase domain as bait. Four out of twelve clones are both His and β-gal positive, one of which encodes the C-terminus of UNC5B ( Figure 1A). In HEK293 cells, transfected GFP-PIKE-L selectively binds to 569-946 fragment of UNC5B but not other fragments. Compared to the binding by the C-terminal motif (a.a. 569-946), truncation of death domain (a.a. 854-946) decreases UNC5B affinity to PIKE-L. Reciprocal immunoprecipitation reveals that the interaction occurs no matter PIKE-L or UNC5B is precipitated by its antibody ( Figure 1B, middle panels). Full-length UNC5B and its C-terminal fragment released after caspase cleavage 5 , 7 specifically interact with GTPase domain but not with other regions of PIKE-L, consistent with our yeast two-hybrid findings ( Figure 1B, right panels). We also 5To whom all correspondence should be addressed, Phone: 404-712-2814; Fax: 404-712-2979, kye@emory observed the robust interaction between endogenous PIKE-L and UNC5B in both the cortex and hippocampus of rat brain ( Figure 1C). Immunostaining of hippocampal and cortical primary neurons reveals that PIKE-L and UNC5B colocalize in the cell body and throughout all neuronal processes ( Figure 1D, left panel). The staining is specific as GST-PIKE-L (a.a. 268-384) antigen but not control GST abolishes PIKE-L staining in neurons ( Figure 1D, right panels).To examine whether netrin-1 modulates PIKE-L interaction with UNC5B, we cotransfected UNC5B into...

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supporting

confidence: 67%

“…PIKE can be phosphorylated on tyrosine residues by Fyn 14 . Netrin-1 has also been shown to trigger its receptor DCC tyrosine phosphorylation 15 -18 .…”

mentioning

confidence: 99%

Netrin-1 mediates neuronal survival through PIKE-L interaction with the dependence receptor UNC5B

et al. 2008

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“…Fyn is intimately correlated with the phosphoinositide-3-kinase/Akt signaling pathway (Lue et al, 2007;Tang et al, 2007;Holen et al, 2008) and prompts proliferation and differentiation (Kim et al, 2010). Akt plays an important role in cell survival and the development of cancer (Brauer and Tyner, 2009).…”

Section: Discussionmentioning

confidence: 99%

Fyn arrests swainsonine-induced apoptosis in 293T cells via Akt and its phosphorylation

Cheng

2015

Genet. Mol. Res.

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ABSTRACT. Swainsonine (SW), an extract from Astragalus membranaceus, represents a new class of compounds that inhibit growth and induce apoptosis in a cancer model. In this study, we demonstrated the effect of Fyn on SW-induced apoptosis in 293T cells. Western blotting was used to measure the expression of the apoptosis-related factors caspase-3, Bcl-2, Bax, and the key factor Akt (also known as protein kinase B). Apoptosis increased dramatically after treatment with SW. Unlike the control group, after transfection with Fyn, the expression of Bcl-2, in contrast to Bax, was markedly upregulated. The results also showed that the protein expression levels of Akt and phosphorylated Akt were markedly increased. Our results establish that Fyn can arrest SW-induced apoptosis via the activity of Akt and its effective phosphorylation in 293T cells.

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“…28 Further, PIKE-A interacts with insulin receptor and mediates its suppressive effect on AMPK activation. 29 Previously, we have reported that Fyn phosphorylates PIKE-A on both Y682 and Y774 30 and regulates its interaction with different partners, promoting neuronal survival 31 and adiposeness. 32 In this report, we provide new evidence supporting that Fyn phosphorylation of PIKE-A is critical for its association with AMPK and inhibition of its kinase activity, leading to the blockade of cell proliferation.…”

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confidence: 99%

Fyn-phosphorylated PIKE-A binds and inhibits AMPK signaling, blocking its tumor suppressive activity

Zhang

Chan

et al. 2015

Cell Death Differ

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The AMP-activated protein kinase, a key regulator of energy homeostasis, has a critical role in metabolic disorders and cancers. AMPK is mainly regulated by cellular AMP and phosphorylation by upstream kinases. Here, we show that PIKE-A binds to AMPK and blocks its tumor suppressive actions, which are mediated by tyrosine kinase Fyn. PIKE-A directly interacts with AMPK catalytic alpha subunit and impairs T172 phosphorylation, leading to repression of its kinase activity on the downstream targets. Mutation of Fyn phosphorylation sites on PIKE-A, depletion of Fyn, or pharmacological inhibition of Fyn blunts the association between PIKE-A and AMPK, resulting in loss of its inhibitory effect on AMPK. Cell proliferation and oncogenic assays demonstrate that PIKE-A antagonizes tumor suppressive actions of AMPK. In human glioblastoma samples, PIKE-A expression inversely correlates with the p-AMPK levels, supporting that PIKE-A negatively regulates AMPK activity in cancers. Thus, our findings provide additional layer of molecular regulation of the AMPK signaling pathway in cancer progression.

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Src-family tyrosine kinase fyn phosphorylates phosphatidylinositol 3-kinase enhancer-activating Akt, preventing its apoptotic cleavage and promoting cell survival

Cited by 48 publications

References 30 publications

Netrin-1 mediates neuronal survival through PIKE-L interaction with the dependence receptor UNC5B

Netrin-1 mediates neuronal survival through PIKE-L interaction with the dependence receptor UNC5B

Fyn arrests swainsonine-induced apoptosis in 293T cells via Akt and its phosphorylation

Fyn-phosphorylated PIKE-A binds and inhibits AMPK signaling, blocking its tumor suppressive activity

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