title: Lipid Raft is required for PSGL-1 ligation induced HL-60 cell adhesion on ICAM-1.
abstract: P-selectin glycoprotein ligand-1 (PSGL-1) and integrins are adhesion molecules that play critical roles in host defense and innate immunity. PSGL-1 mediates leukocyte rolling and primes leukocytes for integrin-mediated adhesion. However, the mechanism that PSGL-1 as a rolling receptor in regulating integrin activation has not been well characterized. Here, we investigate the function of lipid raft in regulating PSGL-1 induced β2 integrin-mediated HL-60 cells adhesion. PSGL-1 ligation with antibody enhances the β2 integrin activation and β2 integrin-dependent adhesion to ICAM-1. Importantly, with the treatment of methyl-β-cyclodextrin (MβCD), we confirm the role of lipid raft in regulating the activation of β2 integrin. Furthermore, we find that the protein level of PSGL-1 decreased in raft fractions in MβCD treated cells. PSGL-1 ligation induces the recruitment of spleen tyrosine kinase (Syk), a tyrosine kinase and Vav1 (the pivotal downstream effector of Syk signaling pathway involved in cytoskeleton regulation) to lipid raft. Inhibition of Syk activity with pharmacologic inhibitor strongly reduces HL-60 cells adhesion, implicating Syk is crucial for PSGL-1 mediated β2 integrin activation. Taken together, we report that ligation of PSGL-1 on HL-60 cells activates β2 integrin, for which lipid raft integrity and Syk activation are responsible. These ﬁndings have shed new light on the mechanisms that connect leukocyte initial rolling with subsequent adhesion.
authors: Institute of Genetics and Cytology, Northeast Normal University, Changchun, Jilin Province, China.
authors: Tingshuang
authors: T
authors: Xu
authors: Wenai
authors: W
authors: Liu
authors: Jixian
authors: J
authors: Luo
authors: Chunfeng
authors: C
authors: Li
authors: Xueqing
authors: X
authors: Ba
authors: Khamal Kwesi
authors: KK
authors: Ampah
authors: Xiaoguang
authors: X
authors: Wang
authors: Yong
authors: Y
authors: Jiang
authors: Xianlu
authors: X
authors: Zeng
mesh_terms: D018821:CD18 Antigens / Q000378:metabolism; D002448:Cell Adhesion; D004789:Enzyme Activation; D018922:HL-60 Cells; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism*; D021962:Membrane Microdomains / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051567:Proto-Oncogene Proteins c-vav / Q000378:metabolism; D000072377:Syk Kinase
chemical_list: D018821:CD18 Antigens; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; C084882:P-selectin ligand protein; D051567:Proto-Oncogene Proteins c-vav; C496618:VAV1 protein, human; D018799:Intercellular Adhesion Molecule-1; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase