Cullin5 destabilizes Cas to inhibit Src-dependent cell transformation

Teckchandani, Anjali; Laszlo, George S.; Simó, Sergi; Shah, Khyati H.; Pilling, Carissa; Strait, Alexander A.; Cooper, Jonathan A.

doi:10.1242/jcs.127829

Cited by 33 publications

(67 citation statements)

References 55 publications

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“…We previously reported that Cul5 inhibits the epidermal growth factor (EGF)-independent migration of MCF10A epithelial cells (Teckchandani et al, 2014). Cul5-depleted cells migrate considerably faster than control cells and have an exaggerated leading lamellipodium bearing tiny FAs, few stress fibers and dynamic membrane ruffles.…”

Section: Resultsmentioning

confidence: 99%

The ubiquitin-proteasome system regulates focal adhesions at the leading edge of migrating cells

Teckchandani

Cooper

2016

eLife

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Cell migration requires the cyclical assembly and disassembly of focal adhesions. Adhesion induces phosphorylation of focal adhesion proteins, including Cas (Crk-associated substrate/p130Cas/BCAR1). However, Cas phosphorylation stimulates adhesion turnover. This raises the question of how adhesion assembly occurs against opposition from phospho-Cas. Here we show that suppressor of cytokine signaling 6 (SOCS6) and Cullin 5, two components of the CRL5SOCS6 ubiquitin ligase, inhibit Cas-dependent focal adhesion turnover at the front but not rear of migrating epithelial cells. The front focal adhesions contain phospho-Cas which recruits SOCS6. If SOCS6 cannot access focal adhesions, or if cullins or the proteasome are inhibited, adhesion disassembly is stimulated. This suggests that the localized targeting of phospho-Cas within adhesions by CRL5SOCS6 and concurrent cullin and proteasome activity provide a negative feedback loop, ensuring that adhesion assembly predominates over disassembly at the leading edge. By this mechanism, ubiquitination provides a new level of spatio-temporal control over cell migration.DOI: http://dx.doi.org/10.7554/eLife.17440.001

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Section: Resultsmentioning

confidence: 99%

The ubiquitin-proteasome system regulates focal adhesions at the leading edge of migrating cells

Teckchandani

Cooper

2016

eLife

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“…The full picture is more complicated, however. Combined knockdown of several SOCS proteins is required to stimulate cell migration to the same extent as Cul5 (130). SOCS7 knockdown stimulates migration of some cancer cell lines (134).…”

Section: Cell Regulation By Crl5: Studies With Cul5 and Rbx2mentioning

confidence: 99%

“…Along these lines, the removal of Cul5 and/or Rbx2 from fibroblasts, epithelial cells, and developing brain increases the level of active but not inactive Src and Fyn proteins but not mRNA (128,(130)(131)(132)(133). This suggests that CRL5 complexes regulate Src/Fyn stability, but changes in half-life have not been reported.…”

Section: Cell Regulation By Crl5: Studies With Cul5 and Rbx2mentioning

confidence: 99%

“…Knockdown or knockout of Cul5 or Rbx2 also increases fibroblast transformation and epithelial cell proliferation and migration, depending on Src, suggesting that the pY substrates are involved (130)(131)(132)(133). The specific pY substrates suppressed by Cul5 in fibroblasts are not known, but the Src substrate p130Cas is required for the increased proliferation and migration of Cul5-deficient epithelial cells (130). p130Cas turnover requires Src, Cul5, and SOCS6.…”

Section: Cell Regulation By Crl5: Studies With Cul5 and Rbx2mentioning

confidence: 99%

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Cell Regulation by Phosphotyrosine-Targeted Ubiquitin Ligases

Cooper

Kaneko

2015

Molecular and Cellular Biology

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Three classes of E3 ubiquitin ligases, members of the Cbl, Hakai, and SOCS-Cul5-RING ligase families, stimulate the ubiquitination of phosphotyrosine-containing proteins, including receptor and nonreceptor tyrosine kinases and their phosphorylated substrates. Because ubiquitination frequently routes proteins for degradation by the lysosome or proteasome, these E3 ligases are able to potently inhibit tyrosine kinase signaling. Their loss or mutational inactivation can contribute to cancer, autoimmunity, or endocrine disorders, such as diabetes. However, these ligases also have biological functions that are independent of their ubiquitination activity. Here we review relevant literature and then focus on more-recent developments in understanding the structures, substrates, and pathways through which the phosphotyrosine-specific ubiquitin ligases regulate diverse aspects of cell biology. Phosphorylation and ubiquitination are among the commonest and best-studied posttranslational modifications of proteins. A phosphate group or ubiquitin molecule can trigger or obstruct protein-protein interactions, alter subcellular localization, stabilize a particular protein conformation, or have myriad other effects. Phosphorylation is directly catalyzed by protein kinases, but ubiquitination is more complex, requiring sequential activity of E1, E2, and E3 ubiquitin-activating, -conjugating, and -ligating enzymes (1-5). E3 ubiquitin ligases fall into two major groups: HECT domain ligases receive ubiquitin from an E2 enzyme and transfer it to a bound substrate, while RING-type ligases position an E2-ubiquitin conjugate near a substrate protein to facilitate ubiquitin transfer. Both phosphorylation and ubiquitination are reversible; protein phosphorylation is reversed by protein phosphatases and ubiquitination by deubiquitinating enzymes (DUBs) (6-8). Therefore, both phosphorylation/dephosphorylation and ubiquitination/deubiquitination can allow repeated cycles of protein modification. Reversible ubiquitination is particularly important in DNA repair and NF-B signaling. However, many ubiquitination events lead irreversibly to protein destruction, allowing regulation of protein turnover. For example, K48 polyubiquitin chains primarily route cytosolic proteins to the proteasome, while modification of many Lys residues with single ubiquitin molecules (multimonoubiquitination) has several functions, including routing membrane proteins for destruction in the lysosome (9-11). The irreversibility of proteolysis means that the ubiquitin-proteasome and ubiquitin-lysosome pathways directly control protein life spans.Protein phosphorylation and ubiquitination cross talk at many levels (12). In this review, we focus on situations where phosphorylation of a substrate creates a binding site for an E3 ligase, rendering ubiquitination dependent on prior phosphorylation of that substrate (13). Such phosphorylation-dependent substrate selection has particular importance because it can layer negative feedback onto an otherwise reversible phosphoryla...

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“…[31] Moreover, silencing CUL5 reduces cellular sensitivity, and endogenous CUL5 suppresses epithelial cell transformation by several pathways, including inhibition of Src-Cas-induced ruffling through SOCS6. [32,33] In the cellular component, the genes in module 3 are principally localized in the nucleus, signalosome, protein complex, and macromalecular complex. The genes in module 71, which are principally detected in the mitochondrial inner membrane presequence translocase complex, participate in protein localization in the mitochondrion and protein targeting to the mitochondrion.…”

Section: Function Enrichment Of Differentially Expressed Modulesmentioning

confidence: 99%