Stathmin Regulates Microtubule Dynamics and Microtubule Organizing Center Polarization in Activated T Cells

Filbert, Erin L.; Borgne, Marie Le; Lin, Joseph; Heuser, John E.; Shaw, Andréy S.

doi:10.4049/jimmunol.1200242

Cited by 42 publications

(38 citation statements)

References 44 publications

(44 reference statements)

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“…Since Stathmin is a regulator of the microtubule network, it is possible that depletion of Stathmin in T-cells affected microtubule stability and dynamics ultimately resulting into reduced motility. Indeed, T-cells lacking Stathmin in Stathmin −/− mice showed delayed microtubule organising centre polymerization, decreased PKCθ polarization, decreased microtubule growth rates32.…”

Section: Discussionmentioning

confidence: 99%

GapmeR cellular internalization by macropinocytosis induces sequence-specific gene silencing in human primary T-cells

Fazil

Ong

Chalasani

et al. 2016

Sci Rep

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Post-transcriptional gene silencing holds great promise in discovery research for addressing intricate biological questions and as therapeutics. While various gene silencing approaches, such as siRNA and CRISPR-Cas9 techniques, are available, these cannot be effectively applied to “hard-to-transfect” primary T-lymphocytes. The locked nucleic acid-conjugated chimeric antisense oligonucleotide, called “GapmeR”, is an emerging new class of gene silencing molecule. Here, we show that GapmeR internalizes into human primary T-cells through macropinocytosis. Internalized GapmeR molecules can associate with SNX5-positive macropinosomes in T-cells, as detected by super-resolution microscopy. Utilizing the intrinsic self-internalizing capability of GapmeR, we demonstrate significant and specific depletion (>70%) of the expression of 5 different endogenous proteins with varying molecular weights (18 kDa Stathmin, 80 kDa PKCε, 180 kDa CD11a, 220 kDa Talin1 and 450 kDa CG-NAP/AKAP450) in human primary and cultured T-cells. Further functional analysis confirms CG-NAP and Stathmin as regulators of T-cell motility. Thus, in addition to screening, identifying or verifying critical roles of various proteins in T-cell functioning, this study provides novel opportunities to silence individual or multiple genes in a subset of purified human primary T-cells that would be exploited as future therapeutics.

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Section: Discussionmentioning

confidence: 99%

GapmeR cellular internalization by macropinocytosis induces sequence-specific gene silencing in human primary T-cells

Fazil

Ong

Chalasani

et al. 2016

Sci Rep

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“…One possibility is that Rac GTPases are involved in the phosphorylation of stathmin, which is required for microtubule remodeling (67). Additionally, stathmin also causes microtubule-organizing center polarization in activated T cells (40), so there is the possibility that cryptococcal mediated microtubule-organizing center polarization in NK cells is regulated by a Rac 3 stathmin pathway.…”

Section: Discussionmentioning

confidence: 99%

Ras-related C3 Botulinum Toxin Substrate (Rac) and Src Family Kinases (SFK) Are Proximal and Essential for Phosphatidylinositol 3-Kinase (PI3K) Activation in Natural Killer (NK) Cell-mediated Direct Cytotoxicity against Cryptococcus neoformans

Xiang

Stack

Huston

et al. 2016

Journal of Biological Chemistry

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The activity of Rac in leukocytes is essential for immunity. However, its role in NK cell-mediated anti-microbial signaling remains unclear. In this study, we investigated the role of Rac in NK cell mediated anti-cryptococcal killing. We found that Cryptococcus neoformans independently activates both Rac and SFK pathways in NK cells, and unlike in tumor killing, Cryptococcus initiated a novel Rac 3 PI3K 3 Erk cytotoxicity cascade. Remarkably, Rac was not required for conjugate formation, despite its essential role in NK cytotoxicity against C. neoformans. Taken together, our data show that, unlike observations with tumor cells, NK cells use a novel Rac cytotoxicity pathway in conjunction with SFK, to kill C. neoformans. NK3 cells are a subset of lymphocytes that have well characterized anti-tumor and anti-viral activity. However, it is now apparent that NK cells also have the capacity to kill microbial targets, which contribute to host defense, and differ in important ways from tumor killing (1). Receptor-mediated NK antitumor signaling depends on sequential activation of PI3K 3 Rac 3 Erk (2); however, because the receptors required for cryptococcal killing differ from those required for tumor killing (3), we predicted that anti-microbial signaling would also differ. Our previous studies have shown that a PI3K 3 Erk signaling pathway was essential for cryptococcal killing (4). Because other laboratories showed that PI3K can activate Erk via either Rac or phospholipase C␥ (PLC␥), we sought to examine the pathway used in NK cell-mediated cryptococcal killing by investigating both PI3K 3 Rac 3 Erk and PI3K 3 PLC␥ 3 Erk pathways (5-9).Rac is a subfamily of Ras homology (Rho) GTPases consisting of Rac1, Rac2, Rac3, and RhoG. They are activated by guanine nucleotide exchange factors by exchanging GDP for GTP (reviewed in Ref. 10). Activation of Rac in NK cells is crucial for conjugate formation between NK and tumor targets (11,12). During tumor killing, Rac-GTP regulates actin remodeling by activating downstream effectors such as WAVE (WASP family verprolin-homologous protein), SRA1 (specifically RAC1-associated protein 1), and p21-activated kinases (PAKs) (13-16). In addition to its important role in cytoskeletal modulation, Rac plays a role in the activation of Erk and NK cell-mediated tumor cytotoxicity (9). Against Raji tumor targets, the human NK cell line, NK92 and primary NK cells required Rac to initiate a PAK1 3 Mek1/2 3 Erk1/2 signaling cascade that allows for cytotoxic granule mobilization and release (2). Rac activation was found to be dependent on PI3K, because NK92 cells transfected with a constitutively active Rac were able to continue killing tumor targets in the presence of PI3K inhibitors, whereas control cells were not (2).In addition to Rac, PLC␥ can also become activated by PI3K and lead to Erk activation. PLC␥ is best known for the production of diacyl glycerol and inositol 3-phosphate, which activates downstream kinases and regulates intracellular calcium (reviewed in Ref. 17). In certain cells,...

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“…The positive staining of stathmin in T lymphocytes is supported by previous studies, as stathmin plays a critical role in the activation of T lymphocytes as a regulator of cell polarization and T lymphocyte migration from the vascular compartment across tissue barriers. [57, 58] The use of stathmin to distinguish the different thymoma subtypes is limited due to its staining of lymphocytes as opposed to the tumorous epithelial cells themselves, as CD4 and CD8 are well-established IHC targets for T lymphocytes. [59]…”

Section: Discussionmentioning

confidence: 99%

Proteomic Signatures of Thymomas

et al. 2016

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Based on the histological features and outcome, the current WHO classification separates thymomas into A, AB, B1, B2 and B3 subtypes. It is hypothesized that the type A thymomas are derived from the thymic medulla while the type B thymomas are derived from the cortex. Due to occasional histological overlap between the tumor subtypes creating difficulties in their separation, the aim of this study was to provide their proteomic characterization and identify potential immunohistochemical markers aiding in tissue diagnosis. Pair-wise comparison of neoplastic and normal thymus by liquid chromatography tandem mass spectrometry (LC-MS/MS) of formalin fixed paraffin embedded tissue revealed 61 proteins differentially expressed in thymomas compared to normal tissue. Hierarchical clustering showed distinct segregation of subtypes AB, B1 and B2 from that of A and B3. Most notably, desmoyokin, a protein that is encoded by the AHNAK gene, was associated with type A thymomas and medulla of normal thymus, by LC-MS/MS and immunohistochemistry. In this global proteomic characterization of the thymoma, several proteins unique to different thymic compartments and thymoma subtypes were identified. Among differentially expressed proteins, desmoyokin is a marker specific for thymic medulla and is potentially promising immunohistochemical marker in separation of type A and B3 thymomas.

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Stathmin Regulates Microtubule Dynamics and Microtubule Organizing Center Polarization in Activated T Cells

Cited by 42 publications

References 44 publications

GapmeR cellular internalization by macropinocytosis induces sequence-specific gene silencing in human primary T-cells

GapmeR cellular internalization by macropinocytosis induces sequence-specific gene silencing in human primary T-cells

Ras-related C3 Botulinum Toxin Substrate (Rac) and Src Family Kinases (SFK) Are Proximal and Essential for Phosphatidylinositol 3-Kinase (PI3K) Activation in Natural Killer (NK) Cell-mediated Direct Cytotoxicity against Cryptococcus neoformans

Proteomic Signatures of Thymomas

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