Arf6: a new player in FcγRIIIA lymphocyte-mediated cytotoxicity

Galandrini, Ricciarda; Micucci, Federica; Tassi, Ilaria; Cifone, Maria Grazia; Cinque, Benedetta; Piccoli, Mario; Frati, Luigi; Santoni, Angela

doi:10.1182/blood-2004-10-4100

Cited by 47 publications

(50 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…28 For N-benzyloxycarbonyl-L-lysine thiobenzyl (BLT) esterase activity, cells were stimulated by plastic-immobilized mAbs or by addition of phorbol-12-myristate-13-acetate (PMA; 50 ng/mL) plus ionomycin (0.5 g/mL). After 4 hours, cell-free supernatants were assayed for BLT esterase (granzyme A) activity on incubation with 0.2 M Tris-HCl, pH 8.1 containing 10 Ϫ4 M BLT and 2.2 ϫ 10 Ϫ4 M dithio-bis-nitrobenzoic acid.…”

Section: Cytotoxic and Degranulation Assaymentioning

confidence: 99%

“…28 When indicated, radiolabeled anti-CD16-treated NK cells were mixed to P815 target cells (E/T ratio ϭ 2:1), briefly centrifuged at 1200 rpm and incubated at 37°C for the indicated times. Chloroform/methanol/HCl lipid extraction was followed by lipid drying under N 2 .…”

Section: Cell Labeling and Phosphoinositide Analysismentioning

confidence: 99%

“…These findings nicely correlate with our previous observations of the role of Arf6 small G protein on CD16-triggered PI5KI␣ activation and lytic granule release. 28 In particular, the activation of PI5KI certainly contributes to Arf6-mediated control of granule exocytosis. 28 Moreover, our data extend previous reports demonstrating a critical role for PI5KI in Ca 2ϩ response induced by B-cell receptor and G protein-coupled receptor.…”

mentioning

confidence: 99%

“…28 In particular, the activation of PI5KI certainly contributes to Arf6-mediated control of granule exocytosis. 28 Moreover, our data extend previous reports demonstrating a critical role for PI5KI in Ca 2ϩ response induced by B-cell receptor and G protein-coupled receptor. 26,48 Our findings indicate that, in contrast to the recurrent theme of functional redundancy among signaling molecules, PI5KI␣ and PI5KI␥ isoforms play a nonredundant role in PIP2 refilling necessary for the proper PLC␥ activity and granule secretion.…”

mentioning

confidence: 99%

See 3 more Smart Citations

PI5KI-dependent signals are critical regulators of the cytolytic secretory pathway

Micucci

Capuano

Marchetti

et al. 2008

Blood

Self Cite

View full text Add to dashboard Cite

Although membrane phospholipid phosphatidylinositol-4,5bisphosphate (PIP2) plays a key role as signaling intermediate and coordinator of actin dynamics and vesicle trafficking, it remains completely unknown its involvement in the activation of cytolytic machinery. By live confocal imaging of primary human natural killer (NK) cells expressing the chimeric protein GFP-PH, we observed, during effector-target cell interaction, the consumption of a preexisting PIP2 pool, which is critically required for the activation of cytolytic machinery. We identified type I phosphatidylinositol-4-phosphate-5-kinase (PI5KI) ␣ and ␥ isoforms as the enzymes responsible for PIP2 synthesis in NK cells. By hRNA-driven gene silencing, we observed that both enzymes are required for the proper activation of NK cytotoxicity and for inositol-1,4,5-trisphosphate (IP3) generation on receptor stimulation. In an attempt to elucidate the specific step controlled by PI5KIs, we found that lytic granule secretion but not polarization resulted in impaired PI5KI␣-and PI5KI␥-silenced cells. Our findings delineate a novel mechanism implicating PI5KI␣ and PI5KI␥ isoforms in the synthesis of PIP2 pools critically required for IP3-dependent Ca 2؉ IntroductionNatural killer (NK) cells and cytotoxic T lymphocytes are critical effectors in the defense against tumor and viral infections 1 ; they exert cytotoxic function through the polarized secretion of granules containing proteolytic molecules, such as perforin and granzymes. This process involves several steps, including the formation of a cytolytic synapse between cytolytic effector and target cell, the rapid reorientation of the microtubule-organizing center along with lytic granules toward the target contact area followed by granule docking and fusion at specialized secretory domains within the cytolytic synapse. 2,3 Several structurally distinct receptors have been implicated in the activation of NK-cell cytolytic machinery: when cross-linked by the corresponding ligands on target cell, they trigger multiple and intersecting signaling pathways responsible for functional activation. 4 A vast array of activating NK receptors belonging to different families are coupled to the lipid modifying enzymes phosphatidylinositol3-kinase (PI3K) and phospholipase C␥ (PLC␥), which provide signals critically required for the activation of the cytolytic machinery [5][6][7][8] ; notably, both enzymes use the membrane phospholipid phosphatidylinositol-4,5-bisphosphate (PIP2) as common substrate. 9 Besides its role as signaling intermediate, PIP2 also acts as critical regulator of various cellular processes, including actin remodeling, membrane and vesicle trafficking, adhesion, and ion transport. 10,11 Surprisingly, the role of PIP2 and its regulatory mechanisms in lymphocyte-mediated cytotoxicity remain completely undefined.The main cellular source of PIP2 are type I phosphatidylinositol-4-phosphate-5-kinase (PI5KI) family members which phosphorylate PI4P on the D5 position of the inositol ring. Three major PI5KI is...

show abstract

Section: Cytotoxic and Degranulation Assaymentioning

confidence: 99%

Section: Cell Labeling and Phosphoinositide Analysismentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

PI5KI-dependent signals are critical regulators of the cytolytic secretory pathway

Micucci

Capuano

Marchetti

et al. 2008

Blood

Self Cite

View full text Add to dashboard Cite

show abstract

“…N ␣ -benzyloxycarbonyl-L-lysine thiobenzyl ester assay for serine esterase was performed as previously described ( 14 ), except that pNK cells were preincubated at least overnight with 100 U/ml IL-2. PNK cells were stimulated with plate-bound anti-CD16 and K562 target cells (E/T ratio 1:1).…”

Section: Cells and Inhibitorsmentioning

confidence: 99%

Myosin IIA is required for cytolytic granule exocytosis in human NK cells

Andzelm¹,

Chen²,

Krzewski³

et al. 2007

J Cell Biol

View full text Add to dashboard Cite

Signal Transduction During Activation and Inhibition of Natural Killer Cells

2010

View full text Add to dashboard Cite

Natural killer (NK) cells are important for early immune responses to viral infections and cancer. Upon activation, NK cells secrete cytokines and chemokines, and kill sensitive target cells by releasing the content of cytolytic granules. This unit is focused on the signal transduction pathways that regulate NK cell activities in response to contact with other cells. We will highlight signals regulating NK cell adhesion to target cells and describe the induction of cellular cytotoxicity by the engagement of different NK cell activation receptors. Negative signaling induced by inhibitory receptors opposes NK cell activation and provides an important safeguard from NK cell reactivity toward normal, healthy cells. We will discuss the complex integration of the different signals that occur during interaction of NK cells with target cells. Curr. Protoc. Immunol. 90:11.9B.1‐11.9B.17. © 2010 by John Wiley & Sons, Inc.

show abstract

Arf6: a new player in FcγRIIIA lymphocyte-mediated cytotoxicity

Cited by 47 publications

References 51 publications

PI5KI-dependent signals are critical regulators of the cytolytic secretory pathway

PI5KI-dependent signals are critical regulators of the cytolytic secretory pathway

Myosin IIA is required for cytolytic granule exocytosis in human NK cells

Signal Transduction During Activation and Inhibition of Natural Killer Cells

Contact Info

Product

Resources

About