ADAM10 cleavage of N-cadherin and regulation of cell–cell adhesion and β-catenin nuclear signalling

Membrane cofactor protein CD46 controls complement activation on cells, is a receptor for several pathogens, and modulates immune responses by affecting CD8؉ T cells. Cells can release CD46 in an intact form on membrane vesicles and in a truncated form by a metalloproteolytic cleavage. The mechanism of shedding and its relationship to cell physiology has remained unclear. We have found using RNA interference analysis that a disintegrin and metalloproteinase (ADAM) 10 is responsible for the regulated shedding of the ectodomain of CD46 in apoptotic cells. The shedding of CD46 was initiated with staurosporine and UVB. Exposure of cell cultures to either UVB or staurosporine resulted in changes of cell morphology and detachment of cells from their matrices within 8 -24 h. During this process CD46 was released both in apoptotic vesicles (vCD46) and proteolytically (sCD46) into the medium. Both the metalloproteinase inhibitor GM6001 and RNA interference of ADAM10 completely prevented the release of sCD46 and increased the expression of vCD46 on HaCaT cell vesicles, suggesting that ADAM10 releases sCD46 from the apoptotic vesicles. To explore whether the release of sCD46 is associated with apoptosis we analyzed the effects of caspase inhibitors. As expected, the inhibition of caspase activity attenuated the characteristic features of apoptosis and also decreased the release of sCD46. Our results reveal ADAM10 as an important regulator of CD46 expression during apoptosis. The ADAM10-mediated release of CD46 from apoptotic vesicles may represent a form of strategy to allow restricted complement activation to deal with modified self.Almost ubiquitously expressed membrane cofactor protein CD46 is a complement regulator that protects cells and tissues from complement damage (1). CD46 can also function as a receptor for several pathogens (2). Cross-linking of CD46 initiates signaling events in a number of cell types (3-6). Recently it was found that CD46 can modulate immune responses by affecting CD8 ϩ T cell cytotoxicity, CD4 ϩ T cell proliferation, and the production of interleukin-2, -10, and transforming growth factor-␤ (7). Furthermore, CD46 induces T-regulatory cell 1 phenotype (8). Normally membrane-bound CD46 has been detected in a soluble form in the cerebrospinal fluids of multiple sclerosis patients with a human herpesvirus 6 infection, for which CD46 has been reported to be a receptor (9). The sera from both normal individuals and cancer patients contain three forms of CD46 with the molecular masses of 56, 47, and 29 kDa. The levels of the 56-and 42-kDa forms are increased in the sera of cancer patients (10). Elevated levels of CD46 have been observed in the sera of patients with systemic lupus erythematosus (11); the urine of patients with glomerular diseases contains three molecular mass forms of CD46 (52, 46, and 35 kDa) (12).Matrix metalloproteinases and the closely related a disintegrin and metalloproteinase (ADAM) 2 family of membranebound proteases have the capacity to convert transmembrane proteins into s...

Section: Inhibition Of Apoptosis With the Pan-caspase Inhibitor Z-vadmentioning

confidence: 57%

“…Interestingly, ADAM10, 12, and 17 are activated in response to ROS (20). Furthermore, calcium ionophores stimulate ADAM10-mediated ectodomain shedding (21). In the present work we have identified ADAM10 as the enzyme responsible for the solubilization of the ectodomain of CD46 (sCD46) during apoptosis.…”

mentioning

confidence: 68%

ADAM10-mediated Release of Complement Membrane Cofactor Protein during Apoptosis of Epithelial Cells

Hakulinen

Keski‐Oja

2006

“…In particular, ADAM10 cleaves Notch (28), N-cadherin (29), and the Eph receptor (30), which are all known to undergo subsequent intramembrane proteolysis followed by nuclear signaling. Furthermore, ␤APP, CD44, and E-cadherin all undergo intramembrane proteolysis as well (6).…”

Section: Discussionmentioning

confidence: 99%

A Basolateral Sorting Signal Directs ADAM10 to Adherens Junctions and Is Required for Its Function in Cell Migration

Wild-Bode¹,

Fellerer

Kugler

et al. 2006

ADAM10 (a disintegrin and metalloprotease) initiates regulated intramembrane proteolysis by shedding the ectodomain of a number of different substrates. Shedding is followed by subsequent intramembrane proteolysis leading to the liberation of intracellular domains capable of nuclear signaling. ADAM10 substrates have been found at cell-cell contacts and are apparently involved in cell-cell interaction and cell migration. Here we have investigated the cellular mechanism that guides ADAM10 to substrates at cell-cell contacts. We demonstrate that intracellular trafficking of ADAM10 critically requires a novel sorting signal within its cytoplasmic domain. Sequential deletion of the cytoplasmic domain and site-directed mutagenesis suggest that a potential Src homology 3-binding domain is essential for ADAM10 sorting. In a polarized epithelial cell line this motif not only targets ADAM10 to adherens junctions but is also strictly required for ADAM10 function in E-cadherin processing and cell migration.The ADAM 3 (a disintegrin and metalloprotease) family of metalloproteases is involved in ectodomain shedding of membrane-bound proteins such as cytokines, growth factors, and adhesion molecules that play a role in cell-cell contact formation, cell migration, and neurite outgrowth (1-4). The release of the extracellular domain of cell adhesion proteins, which contains the homophilic binding sites, disengages cell-cell contact and supports cell migration and proliferation. The inhibition of ectodomain shedding promotes fibroblast adhesion through stabilization of focal adhesion contacts, accompanied by increased cell surface levels of N-cadherin (5). Furthermore, for several ADAM substrates not only is the release of the ectodomain functionally relevant but the resulting membrane-bound C-terminal fragments are substrates for regulated intramembrane proteolysis (6, 7). In some cases these intracellular fragments are involved in signal transduction as has been shown for Notch1-4, N-cadherin, CD44, ErbB4, and the receptor protein tyrosine phosphatase (8 -10). Regulation of intramembrane proteolysis is thought to occur at least in part at the level of ectodomain shedding, because shedding is known to be a prerequisite for the subsequent intramembraneous cut (11, 12).Specifically, ADAM10, which represents a major ␣-secretase activity (13), plays an important role in shedding of Alzheimer disease ␤-amyloid precursor protein (␤APP). Alzheimer disease is characterized by excessive deposition of amyloid ␤-peptide (A␤) in the brain parenchyma. A␤ is generated from ␤APP by proteolytic processing involving ␤-and ␥-secretase (6). The competitive non-amyloidogenic pathway, where ␤APP is initially cleaved by ␣-secretase within the amyloid domain, prevents A␤ generation (14). Overexpression of ADAM10 prevents amyloid pathology, whereas expression of a dominant negative variant enhances A␤ deposition in a transgenic mouse model (15). Thus ADAM10 is not only a major sheddase involved in signaling cascades but also an important therapeutic ta...

“…Alternatively, as yet unidentified cytoplasmic partners of PCDH12 may be released after PCDH12 cleavage and may translocate to the nucleus. This type of mechanism has been demonstrated for ␤-catenin after N-or E-cadherin proteolysis (41,42).…”

Section: Protocadherin-12 Sheddingmentioning

confidence: 99%

“…ADAM10 cleaves other members of the cadherin family, including N-, E-, and VE-cadherins as well as Pcdh ␥ B4 and C3 (41)(42)(43)(44). Therefore, ADAM10-dependent shedding may be a general mechanism of irreversible intercellular junction disruption, as opposed to intracellular phosphorylation for example, which is only transient.…”

Section: Protocadherin-12 Sheddingmentioning

confidence: 99%

Protocadherin-12 Cleavage Is a Regulated Process Mediated by ADAM10 Protein

Bouillot

Tillet

Carmona

et al. 2011

Protocadherins are a group of transmembrane proteins with homophilic binding activity, members of the cadherin superfamily. Apart from their role in adhesion, the cellular functions of protocadherins are essentially unknown. Protocadherin (PCDH)12 was previously identified in invasive trophoblasts and endothelial and mesangial cells in the mouse. Invalidation studies revealed that the protein was required for optimal placental development. In this article, we show that its human homolog is abundantly expressed in various trophoblast subtypes of the human placenta and at lower levels in endothelial cells. We demonstrate that PCDH12 is shed at high rates in vitro. The shedding mechanism depends on ADAM10 and results in reduced cellular adhesion in a cell migration assay. PCDH12 is subsequently cleaved by the ␥-secretase complex, and its cytoplasmic domain is rapidly degraded by the proteasome. PCDH12 shedding is regulated by interlinked intracellular pathways, including those involving protein kinase C, PI3K, and cAMP, that either increase or inhibit cleavage. In endothelial cells, VEGF, prostaglandin E 2 , or histamine regulates PCDH12 shedding. The extracellular domain of PCDH12 was also detected in human serum and urine, thus providing evidence of PCDH12 shedding in vivo. Importantly, we observed an increase in circulating PCDH12 in pregnant women who later developed a pre-eclampsia, a frequent pregnancy syndrome and a major cause of maternal and fetal morbidity and mortality. In conclusion, we speculate that, like in mice, PCDH12 may play an important role in human placental development and that proteolytic cleavage in response to external factors, such as cytokines and pathological settings, regulates its activity.The cadherin superfamily is composed of membrane proteins with Ca 2ϩ -dependent cell adhesion properties and homologous sequence repeats located in their extracellular domains (1-3). These repeats are responsible for the homophilic adhesive behavior of members of the cadherin family. Four groups of cadherins have been identified so far: the "classical" type I and type II cadherins; the desmosomal cadherins; and the most recently discovered protocadherin family. Protocadherins were initially discovered by PCR cloning using cadherin homology sequences (4). With genome sequencing, more than 70 different protocadherin genes have been identified altogether. This makes protocadherins the largest subgroup within the cadherin superfamily (5). Most protocadherin genes are clustered in three loci: protocadherin (Pcdh) 3 ␣, ␤, and ␥.