The Adaptor Molecule CIN85 Regulates Syk Tyrosine Kinase Level by Activating the Ubiquitin-Proteasome Degradation Pathway

Peruzzi, Giovanna; Molfetta, Rosa; Gasparrini, Francesca; Vian, Laura; Morrone, Stefania; Piccoli, Mario; Frati, Luigi; Santoni, Angela; Paolini, Rossella

doi:10.4049/jimmunol.179.4.2089

Cited by 21 publications

(27 citation statements)

References 51 publications

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“…While a time-dependent decrease of Syk expression (∼50%) was observed in line with previous reported susceptibility of Syk to proteolysis [17,31,32], Hrs expression remained substantially stable until 8 h after FcεRI engagement, supporting the notion that Hrs modifications do not act as a degradation signal on mast cells. All together, our findings indicate that Syk/Cbl-induced Hrs modifications, without affecting protein stability, might impact on the ability of Hrs to function as endocytic adapter.…”

Section: Phosphorylation and Monoubiquitination Of Hrs Control Its Mesupporting

confidence: 73%

Syk‐dependent regulation of Hrs phosphorylation and ubiquitination upon FcεRI engagement: Impact on Hrs membrane/cytosol localization

et al. 2012

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Several lines of evidence suggest that Syk controls immune receptor endocytic trafficking. However, the Syk substrates that regulate this process are not currently known. Here, we demonstrate that Syk knockdown prevents the trafficking of engaged high affinity IgE receptor (FcεRI) to a degradative compartment in mast cells. We then concentrate our attention on hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs) as potential Syk substrate, since it serves as critical regulator for FcεRI entry into lysosomes. We show that Hrs undergoes antigen-dependent tyrosine phosphorylation and ubiquitination, and identify Syk as the kinase responsible for Hrs phosphorylation. Syk was also required for Hrs ubiquitination catalyzed by c-Cbl E3 ligase. Syk-dependent regulation of Hrs covalent modifications, without affecting protein stability, controlled Hrs localization. The majority of phosphorylated Hrs forms were observed only in membrane compartments, whereas ubiquitinated Hrs was predominantly cytosolic, suggesting that both modifications might impact on Hrs function. Together, these findings provide a major step forward in understanding how Syk orchestrates endocytosis of engaged immune receptors.Keywords: FcεRI r Hrs r Phosphorylation r Syk kinase r Ubiquitination Supporting Information available online IntroductionThe Syk/ZAP-70 family of protein tyrosine kinases (PTKs) plays an essential role in signaling through a variety of immune receptors (IRs), including the TCR and BCR, the high-affinity receptor for IgE (FcεRI), and the widely distributed receptors for IgG [1]. All these IRs contain multiple subunits; some, unique for each receptor, are used for ligand binding whereas others share a conserved ITAM Correspondence: Prof. Rossella Paolini e-mail: rossella.paolini@uniroma1.it that is rapidly phosphorylated by PTKs of the Src family upon IR aggregation, thus allowing signal propagation [2,3].IR-mediated signals also lead to a negative-feedback regulation by the internalization and delivery of engaged receptor complexes to lysosomes for degradation [4][5][6][7][8][9][10][11].In the past years, we have concentrated our interest on the molecular mechanisms responsible for ligand-induced endocytosis of IRs, mainly focusing on the FcεRI that is constitutively expressed on the membrane of mast cells and basophils. FcεRI is composed of an IgE-binding α chain, and the ITAM-containing β and γ subunits [12]. Upon FcεRI cross-linking, the β chainassociated Src family PTK Lyn, phosphorylates β and γ-chain We have previously demonstrated that upon antigen stimulation FcεRI β and γ subunits are ubiquitinated through the combined enzymatic activities of the PTK Syk and the Ub ligase c-Cbl [17]. More recently, we provided evidence that this modification controls receptor internalization and sorting along the endocytic compartments through the action of Ub-binding adapters [11,18,19]. Notably, we have envisaged a critical role for the hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs) in controlling the...

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Section: Phosphorylation and Monoubiquitination Of Hrs Control Its Mesupporting

confidence: 73%

Syk‐dependent regulation of Hrs phosphorylation and ubiquitination upon FcεRI engagement: Impact on Hrs membrane/cytosol localization

et al. 2012

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“…Several models have previously reported that retarding endocytosis of IgE/FcεRI complexes - through deletion of RabGEF1/Rabex-5, a guanosine nucleotide exchange factor (50), or by using cytochalasin D or latrunculin to block actin polymerization (39, 51) - resulted in elevated FcεRI signaling and production of specific cytokines by MCs. Similarly, accelerating the sorting of IgE/FcεRI complexes into early endosome/lysosomes by overexpression of CIN85, a molecule that regulates IgE/FcεRI endocytosis, resulted in attenuated FcεRI signaling (22,52). These prior studies, together with our current findings, highlight the largely overlooked role of MC endocytic circuitry and the intracellular location of these activities in regulating duration of mediator responses to allergens.…”

Section: Discussionmentioning

confidence: 48%

Particulate allergens potentiate allergic asthma in mice through sustained IgE-mediated mast cell activation

Jin¹,

Shelburne²,

Li³

et al. 2011

J. Clin. Invest.

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Allergic asthma is characterized by airway hyperresponsiveness, inflammation, and a cellular infiltrate dominated by eosinophils. Numerous epidemiological studies have related the exacerbation of allergic asthma with an increase in ambient inhalable particulate matter from air pollutants. This is because inhalable particles efficiently deliver airborne allergens deep into the airways, where they can aggravate allergic asthma symptoms. However, the cellular mechanisms by which inhalable particulate allergens (pAgs) potentiate asthmatic symptoms remain unknown, in part because most in vivo and in vitro studies exploring the pathogenesis of allergic asthma use soluble allergens (sAgs). Using a mouse model of allergic asthma, we found that, compared with their sAg counterparts, pAgs triggered markedly heightened airway hyperresponsiveness and pulmonary eosinophilia in allergen-sensitized mice. Mast cells (MCs) were implicated in this divergent response, as the differences in airway inflammatory responses provoked by the physical nature of the allergens were attenuated in MC-deficient mice. The pAgs were found to mediate MC-dependent responses by enhancing retention of pAg/IgE/FcεRI complexes within lipid raft-enriched, CD63 + endocytic compartments, which prolonged IgE/ FcεRI-initiated signaling and resulted in heightened cytokine responses. These results reveal how the physical attributes of allergens can co-opt MC endocytic circuitry and signaling responses to aggravate pathological responses of allergic asthma in mice.

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“…As previously mentioned, it is becoming evident that Cbl proteins play a critical role in the function of CIN85 in immune cells. [20][21][22] In addition, BCR-induced association of CIN85 with c-Cbl was recently shown even in mouse B cells. 44 We thus find that in human B cells, CIN85 negatively regulates BCR signaling via a Cbl-dependent mechanism.…”

Section: Discussionmentioning

confidence: 94%

“…20 In addition, it regulates Fc⑀RI signaling via Cbl-mediated regulation of Syk expression in RBL-2H3 cells. 21 A recent study showed that CIN85 modulates c-Cbl-mediated down-regulation of Fc␥RIIa in human neutrophils. 22 It is thus of interest to determine whether CIN85 regulates the signaling pathways of other multimeric immune receptors, such as the T-and B-cell receptors.…”

Section: Introductionmentioning

confidence: 99%

CIN85 is required for Cbl-mediated regulation of antigen receptor signaling in human B cells

Niiro

Jabbarzadeh-Tabrizi

Kikushige

et al. 2012

Blood

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IntroductionB-cell receptor (BCR) signaling guides critical cell fate decisions in B cells during ontogeny. 1,2 BCRs can generate tolerogenic signals to purge or silence B cells that bind to self-antigens, and immunogenic signals to expand B cells that are specific for foreign antigens. Thus, BCR signaling must be properly regulated at the various stages of B-cell development, as aberrant regulation of BCR signaling potentially leads to autoimmunity and B-cell malignancies.On BCR ligation by antigens, the Src-family protein tyrosine kinase (PTK) Lyn and Syk are initially activated. Syk propagates the signal by phosphorylating downstream signaling molecules, causing the activation of critical signaling intermediates phosphoinositol 3-kinase (PI3K) and phospholipase C (PLC)␥2. PI3K activates Akt kinase, which is important for B-cell survival. 3 PLC␥2 activation induces the release of intracellular Ca 2ϩ and the activation of protein kinase C (PKC), which cause the activation of mitogen-activated protein kinases (MAPKs; ERK, JNK, and p38 MAPK) and of transcription factors, including NF-B and NF-AT. These molecules regulate further downstream molecules that are responsible for determining B-cell fates such as survival, growth, and differentiation. 1,2 Casitas B-lineage lymphoma (Cbl) proteins are E3 ubiquitin ligases that regulate signals of various receptors by promoting the ubiquitination of signaling components. 4,5 Tyrosine phosphorylation of Cbl proteins is critical for their function. 6 Mammalian Cbl proteins consist of 3 members, c-Cbl, Cbl-b, and Cbl-3, among which c-Cbl and Cbl-b are expressed in hematopoietic cells. 7 In B cells, Cbl proteins associate with Syk and B-cell linker (BLNK), and negatively regulate BCR signaling. 8,9 B cell-specific ablation of c-Cbl/Cbl-b proteins in mice causes aberrant BCR signaling as well as impaired B-cell anergy, culminating in the development of systemic lupus erythematosus (SLE)-like disease. 10 In addition, c-Cbl is hypophosphorylated on tyrosine in advanced stages of chronic lymphocytic leukemia (CLL). 11 These findings suggest that Cbl-mediated regulation of BCR signaling is critical for the fate decisions of self-reactive and malignant B cells.Adaptors are noncatalytic molecules that integrate the spatial and temporal assembly of multiprotein complexes involved in the survival, growth, and differentiation of B cells. We previously showed that the B lymphocyte adaptor molecule of 32 kDa (Bam32)/DAPP1 regulates BCR signaling/internalization and B-cell survival. 12,13 The SH3KBP1 (SH3-domain kinase-binding protein 1) gene, which is also known as CIN85 (c-Cbl interacting protein of 85 kDa), encodes an adaptor that is independently identified by several groups and contains 3 SH3 domains, a proline-rich region, and a coiled-coil domain. [14][15][16][17] Early studies showed that in nonimmune cells, CIN85 regulates the clathrindependent internalization of receptor tyrosine kinases (RTKs) such as epidermal growth factor receptors (EGFRs). 18,19 The formation of the ternary...

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The Adaptor Molecule CIN85 Regulates Syk Tyrosine Kinase Level by Activating the Ubiquitin-Proteasome Degradation Pathway

Cited by 21 publications

References 51 publications

Syk‐dependent regulation of Hrs phosphorylation and ubiquitination upon FcεRI engagement: Impact on Hrs membrane/cytosol localization

Syk‐dependent regulation of Hrs phosphorylation and ubiquitination upon FcεRI engagement: Impact on Hrs membrane/cytosol localization

Particulate allergens potentiate allergic asthma in mice through sustained IgE-mediated mast cell activation

CIN85 is required for Cbl-mediated regulation of antigen receptor signaling in human B cells

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