L-Selectin Regulates Actin Polymerisation via Activation of the Small G-Protein Rac2

doi:10.1006/bbrc.1997.6191

Biochemical and Biophysical Research Communications

Volume 231, Issue 3, 24 February 1997, Pages 802-807

https://doi.org/10.1006/bbrc.1997.6191 Get rights and content

Abstract

L-selectin mediated adhesion to endothelial cells is a crucial step in the immune response to pathogens (1, 2) and in lymphocyte homing (3, 4). Selectin molecules mediate leukocyte rolling on endothelial cells, the initial step of adhesion (5, 6). We have previously shown that stimulation of Jurkat T-lymphocytes via L-selectin results in activation of the p21Ras pathway and synthesis of reactive oxygen intermediates (7). Here, we show that cellular stimulation via L-selectin induces a change of cytoskeleton organisation demonstrated by a tenfold increase of actin filament polymerisation. This actin polymerisation is mediated by a Ras and Rac2 regulated pathway, since inhibition of Ras by transient transfection of transdominant inhibitory N17Ras or suppression of Rac2 protein expression by antisense oligonucleotides prevents L-selectin triggered actin polymerisation. Our results point to a signaling cascade from L-selectin via Ras and Rac2 to actin filaments, which might be important for leukocyte adhesion.

References (45)

T.A. Springer
Cell
(1994)
E.C. Butcher
Cell
(1991)
R.F. Bargatze et al.
Immunity
(1995)
M.B. Lawrence et al.
Cell
(1991)
M.A. Jutila et al.
Blood
(1990)
M.L. Arbonés et al.
Immunity
(1994)
T.K. Kishimoto et al.
Blood
(1991)
G.J. Tangelder et al.
Blood
(1991)
R.M. Nelson et al.
Blood
(1993)
K. Ley et al.
Blood
(1993)

Cited by (60)

L-selectin activation regulates Rho GTPase activity via Ca<sup>+2</sup> influx in Sertoli cell line, ASC-17D cells
2020, Biochemical and Biophysical Research Communications
In seminiferous epithelium, tight junctions (TJs) between adjacent Sertoli cells constitute the blood-testis barrier and must change synchronically for germ cells to translocate from the basal to the adluminal compartment during the spermatogenic cycle. Rho GTPase activation through stimulation with specific L-selectin ligands has been proposed to modulate tight junctional dynamics. However, little is known regarding the role of Ca⁺² dynamics in Sertoli cell and how Ca⁺² relays L-selectin signals to modulate Rho GTPase activity in Sertoli cells, thus prompting us to investigate the Ca⁺² flux induced by L-selectin ligand in ASC-17D cells. Using fluorescent real-time image, we first demonstrated the increase of intracellular Ca⁺² level following L-selectin ligand stimulation. This Ca⁺² increase was inhibited in ASC-17D cells pretreated with nifedipine, the L-type voltage-operated Ca⁺² channel (VOCC) blocker, but not mibefradil, the T-type VOCC blocker. We then demonstrated the up-regulation of Rho and Rac1 in ASC-17D cells following the administration of L-selectin ligand, and the pre-treatment with nifedipine, but not mibefradil, prior to L-selectin ligand-binding abolished the activation of both Rho and Rac1. Together, we conclude that the activation of L-selectin induces Ca⁺² influx through the L-type VOCC, which up-regulates Rho and Rac1 proteins, in ASC-17D cells.
Role of L-selectin on leukocytes in the binding of sialic acids on sperm surface during the phagocytosis of sperm in female reproductive tract
2018, Medical Hypotheses
Citation Excerpt :
In addition to mainly mediating leukocytes capturing and rolling on the endothelial cells, L-selectin plays an important role in the activation of multiple biochemical signaling pathways [9,10], such as the mitogen-activated protein kinase (MAPK) cascade [11]. Brenner et al. found that L selectin crosslink ligands can cause the activation of signaling pathways, which are involved in participation with p56, Grb2/Sos, Ras, MAPK and Rac2, transmit the signals that initiated by the L selectin crosslinking into the cells, eventually lead to the generation of superoxide and the changes of cytoskeleton [12]. Our hypothesis is that during the sperm phagocytosis in female reproductive tract, leukocytes identify the sialic acids on the sperm surface through L-selectin which is on leukocytes surface to bind the sperm, followed by activation of downstream phagocytic signaling pathway and serials of intricate physiological responses resembling the leukocytes phagocytize foreign materials, eventually eliminating the sperm (Fig. 1).
In either natural fertilization or artificial insemination, hundreds of millions of sperm are ejaculated or inseminated and then deposited in the female reproductive tract, but only a few sperm reach the ampulla or the site of fertilization. This dramatic reduction in numbers clearly highlights the obstacles that sperm must overcome in order to reach the destination for egg fertilizing. Phagocytosis of sperm by leukocytes are repeatedly observed and generally considered to be one of the most important barriers, but the mechanism of the phagocytosis of sperm remains unclear. L-selectin is constitutively expressed on leukocytes, which can influence the behaviors of leukocytes when bind to ligands. Sialic acids are found as the outer most monosaccharide, capping the majority of glycans at the sperm surface, can act as recognition molecule. Since the sialic acids are considered as ligands of L-selectin, we propose that leukocytes bind to the sperm through the L-selectin on leukocytes and sialic acid on sperm surface during the sperm phagocytosis in female reproductive tract.
L-Selectin - A dynamic regulator of leukocyte migration
2012, European Journal of Cell Biology
Citation Excerpt :
In conjunction with its adhesive function, l-selectin mediates outside-in and inside-out signaling in leukocytes. Ligation of l-selectin with antibody or ligand elicits a number of cellular events, including elevated Ca2+ and phosphotyrosine protein levels (Laudanna et al., 1994; Waddell et al., 1995), synthesis of reactive oxygen compounds (Waddell et al., 1994), activation of the mitogen-activated protein kinases extracellular regulated kinase and Jun N-terminal kinase (Brenner et al., 1996, 1997b), and Rac-mediated rearrangements of the actin cytoskeleton (Brenner et al., 1997a). Furthermore, l-selectin triggers the enhanced binding activity of both β1 and β2 integrins (Hwang et al., 1996; Giblin et al., 1997).
The leukocytic cell adhesion receptor l-selectin mediates the initial step of the adhesion cascade, the capture and rolling of leukocytes on endothelial cells. This event enables leukocytes to migrate out of the vasculature into surrounding tissues during inflammation and immune surveillance. Distinct domains of l-selectin contribute to proper leukocyte migration. In this review, we discuss the contributions of these domains with respect to l-selectin function: the regulation by serine phosphorylation of the cytoplasmic tail, the role of the transmembrane domain in receptor positioning on the cell surface as well as the N-glycosylation of the extracellular part and the identification of novel binding partners.
Role of c-Abl in L-selectin shedding from the neutrophil surface
2011, Blood Cells, Molecules, and Diseases
Citation Excerpt :
TNF-α-converting enzyme (TACE or ADAM-17) was identified as the protease responsible for L-selectin cleavage [27,28]. Crosslinking of L-selectin with anti-L-selectin mAb or stimulation with sialyl Lewis-x under static conditions leads to the activation of a signaling cascade from tyrosine kinase p56lck to Sos, Ras, MAPK, and Rac2 [29,30]. We previously found that L-selectin is shed from the neutrophil surface as a result of the mechanical stimulus stemming from neutrophil rolling on a sialyl Lewis-x coated surface under shear flow [31].
L-selectin is a key molecule that participates in neutrophil tethering and subsequent rolling. It is cleaved from the surface of neutrophils activated in the presence of lipopolysaccharides, N-formyl-methionine-leucine-phenylalanine (fMLP), or Interleukin-8 (IL-8). We previously showed that L-selectin is also shed from the neutrophil surface during rolling on sialyl Lewis-x coated surfaces in a force-, ADAM-17 sheddase-, and p38 MAP kinase-dependent manner under flow. c-Abl tyrosine kinase is phosphorylated when L-selectin on the surface of neutrophils is cross-linked with anti-L-selectin antibodies. Here, we study the effect of c-Abl inhibition on L-selectin shedding from primary human neutrophils in static conditions following exposure to fMLP, IL-8, and hypotonic buffer and under flow through sialyl Lewis-x coated microtubes. Results indicate that c-Abl inhibition by STI571 significantly affects neutrophil adhesion via L-selectin, by decreasing the average rolling velocity and increasing the flux of rolling cells. The change in surface receptor expression was verified by flow cytometry. Interestingly, other forms of L-selectin shedding induced by fMLP, IL-8 or osmotic swelling were unaffected by STI571 treatment. These findings implicate the c-Abl signaling molecule in regulating L-selectin mechanical shedding in response to shear stress, setting this type of signaling apart from those triggered by the presence of a hypotonic environment, fMLP, or IL-8. This study sheds light on the role of c-Abl in neutrophil adhesion not previously reported in the literature.
Cytoskeletal interactions with leukocyte and endothelial cell adhesion molecules
2009, Current Topics in Membranes
Each of the major classes of cell adhesion molecules are necessary for leukocyte trafficking. Selectins, integrins, and immunoglobulin superfamily members all play important roles in cellular immune responses and each have cytoplasmic tails that interact with cytoskeletal proteins. These interactions between cell adhesion molecule cytoplasmic tails and cytoskeletal proteins are essential for immune cell rolling, adhesion, migration, and diapedesis. This chapter describes the progress made to date in characterizing these interactions and focuses on the processes that are most essential to leukocyte rolling and adhesion. The major families of cell adhesion molecules involved in mediating leukocyte rolling, adhesion, and migration each associate with, and are regulated by interactions with, the cytoskeleton. Transendothelial migration requires the participation of both leukocyte and endothelial cell adhesion molecules. This chapter provides an overview of the cytoskeletal interactions that occur between leukocyte and endothelial cell adhesion molecules and discusses how those interactions are thought to regulate adhesive functions that are important for leukocyte trafficking under conditions of fluid shear stress. Although this chapter is limited primarily to discussion of cell adhesion molecules in leukocytes and endothelial cells that are involved in cellular immunity and are regulated through interaction with the actin cytoskeleton, recent reports do suggest a role for endothelial microtubules and kinesins in promoting diapedesis.
L-selectin ligation-induced CSF-1 gene transcription is regulated by AP-1 in a c-Abl kinase-dependent manner
2008, Human Immunology
L-selectin is a cell adhesion molecule that plays an important role both in mediating the initial capture and subsequent rolling of leukocytes along the endothelial cells and in the signal transduction for leukocyte activation. In our previous studies, we reported that L-selectin ligation could increase macrophage colony-stimulating factor (CSF)-1 gene transcription, in which c-Abl acts as a crucial cytoplasmic kinase. Here we investigated the function of the nuclear c-Abl kinase in the CSF-1 gene transcriptional events triggered by L-selectin ligation. We determined that c-Abl kinase recruits to the nucleus following L-selectin ligation, and the nuclear c-Abl kinase can phosphorylate c-Jun and regulate activator protein (AP)-1 activity. Furthermore, the activated c-Abl kinase interacts with AP-1 and forms a complex in the CSF-1 promoter region to regulate CSF-1 gene transcription in the L-selectin ligation-activated cells. These results indicate that nuclear c-Abl kinase can activate CSF-1 gene transcription by regulating AP-1 activity in the signaling events induced by L-selectin ligation.

View all citing articles on Scopus

¹: To whom correspondence should be addressed. Fax: 011-49-6221-564624.

View full text

Regular ArticleL-Selectin Regulates Actin Polymerisation via Activation of the Small G-Protein Rac2

Abstract

Cell

Cell

Immunity

Cell

Blood

Immunity

Blood

Blood

Blood

Blood

J. Biol. Chem.

J. Biol. Chem.

J. Biol. Chem.

Blood

J. Biol. Chem.

Immunity

J. Biol. Chem.

Cell

J. Biol. Chem.

Cell

APMIS

Science

Regular Article
L-Selectin Regulates Actin Polymerisation via Activation of the Small G-Protein Rac2