β1 integrin-dependent cell adhesion to EMILIN-1 is mediated by the gC1q domain
β1 integrin-dependent cell adhesion to EMILIN-1 is mediated by the gC1q domain
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DOI：
10.1074/jbc.m208322200
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发表时间：
2003-02-21
影响因子：
4.8
通讯作者：
Colombatti, A
中科院分区：
文献类型：
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作者：
Spessotto, P;Cervi, M;Colombatti, A
EMILIN-1（弹性蛋白微原纤维界面定位蛋白）是EMILIN家族的原型，由N端的富含半胱氨酸的结构域（EMI结构域）、具有高电位卷曲螺旋结构的延伸区域、短胶原茎和自相互作用的球状gC 1 q-1结构域组成。EMILIN-1是与弹性纤维相关的粘附性细胞外基质成分，也在细胞表面附近检测到。为了定位细胞附着位点，使用针对EMILIN-1或gC 1 q-1结构域的单克隆抗体（mAb）来抑制细胞与EMILIN-1的附着。因此，一种定位于gC 1 q-1结构域的mAb引起细胞附着的完全抑制。EMILIN-1和gC 1 q-1显示出相当的促进细胞粘附的剂量依赖性能力。粘附动力学与纤连蛋白（FN）相似，在20分钟时达到最大粘附水平，但在不存在阳离子的情况下，粘附可以忽略不计。EMILIN-1和gC 1 q-1分离50%细胞的相对粘附强度相似（250-270 x g），但低于FN（远大于500）。细胞粘附EMILIN-1或gC 1 q-1被功能阻断β（1）整合素亚单位mAb完全阻断。相反，补体C1 q成分的粘附完全不受影响。在针对α整联蛋白亚基的各种功能阻断mAb中，仅抗α（4）完全消除细胞对gC 1 q-1的粘附，并高达70%消除细胞对EMILIN-1的粘附。此外，只有用α 4整联蛋白链转染的K562细胞，而不是野生型K562，能够粘附EMILIN-1，并被抗α 4功能阻断mAb特异性抑制。最后，贴附于EMILIN-1或gC 1 q-1的细胞，与贴附于FN或玻连蛋白的细胞相比（FN或玻连蛋白在基底上伸展良好，具有突出的应力纤维和焦点接触）要小得多，具有宽皱褶，并且沿着细胞周边的肌动蛋白细胞骨架沿着具有不同的组织状态。这种模式与EMILIN-1促进细胞运动的能力雅阁。
EMILIN-1 (Elastin Microfibril Interface Located ProteIN), the prototype of the EMILIN family, consists of a cysteine-rich domain (EMI domain) at the N terminus, an extended region with a high potential coiled-coil structure, a short collagenous stalk, and a self-interacting globular gC1q-1 domain. EMILIN-1 is an adhesive extracellular matrix constituent associated with elastic fibers, detected also in the proximity of cell surfaces. To localize the cell attachment site(s), monoclonal antibodies (mAbs) against EMILIN-1 or the gC1q-1 domain were used to inhibit cell attachment to EMILIN-1. Thus, one mAb mapping to the gC1q-1 domain caused complete inhibition of cell attachment. EMILIN-1 and gC1q-1 displayed a comparable dose-dependent ability to promote cell adhesion. Adhesion kinetics was similar to that of fibronectin (FN), reaching the maximum level of attachment at 20 min, but in the absence of cations adhesion was negligible. The relative adhesion strength to detach 50% of the cells was similar for EMILIN-1 and gC1q-1 (250-270 x g) but lower than that for FN (much greater than500). Cell adhesion to EMILIN-1 or gC1q-1 was completely blocked by a function-blocking beta(1) integrin subunit mAb. In contrast, adhesion to the complement C1q component was totally unaffected. Among the various function-blocking mAbs against the alpha integrin subunits only the anti-alpha(4) fully abrogated cell adhesion to gC1q-1 and up to 70% to EMILIN-1. Furthermore, only K562 cells transfected with the alpha(4) integrin chain, but not wild type K562, were able to adhere to EMILIN-1 and were specifically inhibited by anti-alpha(4) function-blocking mAb. Finally, cells attached to EMILIN-1 or gC1q-1, compared with cells plated on FN or vitronectin, which appeared well spread out on the substrate with prominent stress fibers and focal contacts, were much smaller with wide ruffles and a different organization status of the actin cytoskeleton along the cell periphery. This pattern was in accord with the ability of EMILIN-1 to promote cell movement.