Zaman Sabiha N, Resek Mary E, Robbins Stephen M
University of Calgary, Calgary, Alberta, Canada T2N-4N1.
J Leukoc Biol. 2008 Oct;84(4):1082-91. doi: 10.1189/jlb.1007698. Epub 2008 Jul 16.
Chemokines play pivotal roles in regulating a wide variety of biological processes by modulating cell migration and recruitment. Deregulation of chemokine signaling can alter cell recruitment, contributing to the pathogenic states associated with autoimmune disease, inflammatory disorders, and sepsis. During chemotaxis, lipid rafts and their resident signaling molecules have been demonstrated to partition to different parts of the cell. Herein, we investigated the role of lipid raft resident Src-family kinases (SFK) in stromal cell-derived factor 1/CXCL12-mediated chemotaxis. We have shown that Lck-deficient J.CaM 1.6 cells are defective in CXCL12-mediated chemotaxis in contrast to their parental counterpart, Jurkat cells. Ectopic expression of the SFK hematopoietic cell kinase (Hck) in J.CaM 1.6 cells reconstituted CXCL12 responsiveness. The requirement of lipid raft association of SFK was assessed using both isoforms of Hck: the dually acylated p59(Hck) isoform that is targeted to lipid rafts and the monoacylated p61(Hck) isoform that is nonraft-associated. We have shown using several gain and loss of acylation alleles that dual acylation of Hck was required for CXCL12-mediated chemotaxis in J.CaM 1.6 cells. These results highlight the importance of the unique microenvironment provided by lipid rafts and their specific contribution in providing specificity to CXCL12 signaling.
趋化因子通过调节细胞迁移和募集，在调控多种生物学过程中发挥关键作用。趋化因子信号传导失调可改变细胞募集，导致与自身免疫性疾病、炎症性疾病和败血症相关的致病状态。在趋化作用过程中，脂筏及其驻留信号分子已被证明会分布到细胞的不同部位。在此，我们研究了脂筏驻留的Src家族激酶（SFK）在基质细胞衍生因子1/CXCL12介导的趋化作用中的作用。我们已经表明，与亲代Jurkat细胞相比，缺乏Lck的J.CaM 1.6细胞在CXCL12介导的趋化作用中存在缺陷。在J.CaM 1.6细胞中异位表达SFK造血细胞激酶（Hck）可恢复CXCL12反应性。使用Hck的两种同工型评估了SFK与脂筏结合的需求：靶向脂筏的双酰化p59（Hck）同工型和非脂筏相关的单酰化p61（Hck）同工型。我们使用几种酰化等位基因的增减表明，J.CaM 1.6细胞中CXCL12介导的趋化作用需要Hck的双酰化。这些结果突出了脂筏提供的独特微环境的重要性及其在为CXCL12信号传导提供特异性方面的特定贡献。
