Western blot analysis of ZFP36 expressed in WiDr using ZFP36 Rabbit pAb at 1:1000. Secondary antibody: HRP Goat Anti-Rabbit IgG (H+L) at 1:5000. Lysates/proteins: 30ug per lane. Blocking buffer: 5% non-fat dry milk in TBST. Detection: ECL Enhanced Kit. Exposure time: 120s.
Western blot analysis of ZFP36 expressed in WiDr using ZFP36 Rabbit pAb at 1:1000. Secondary antibody: HRP Goat Anti-Rabbit IgG (H+L) at 1:5000. Lysates/proteins: 30ug per lane. Blocking buffer: 5% non-fat dry milk in TBST. Detection: ECL Enhanced Kit. Exposure time: 120s.
Enables several functions, including 14-3-3 protein binding activity; heat shock protein binding activity; and mRNA 3''-UTR AU-rich region binding activity. Involved in several processes, including cellular response to cytokine stimulus; cellular response to growth factor stimulus; and regulation of gene expression. Acts upstream of or within mRNA catabolic process. Located in cytoplasmic ribonucleoprotein granule; cytosol; and nucleus. Part of ribonucleoprotein complex. Colocalizes with RISC-loading complex.
Expressed in both basal and suprabasal epidermal layers (PubMed:27182009). Expressed in epidermal keratinocytes (PubMed:27182009). Expressed strongly in mature dendritic cells (PubMed:18367721). Expressed in immature dendritic cells (at protein level) (PubMed:18367721).
功能
Zinc-finger RNA-binding protein that destabilizes several cytoplasmic AU-rich element (ARE)-containing mRNA transcripts by promoting their poly(A) tail removal or deadenylation, and hence provide a mechanism for attenuating protein synthesis (PubMed:9703499, PubMed:10330172, PubMed:10751406, PubMed:11279239, PubMed:12115244, PubMed:12748283, PubMed:15187101, PubMed:15634918, PubMed:17030620, PubMed:16702957, PubMed:20702587, PubMed:20221403, PubMed:21775632, PubMed:27193233, PubMed:23644599, PubMed:25815583). Acts as an 3'-untranslated region (UTR) ARE mRNA-binding adapter protein to communicate signaling events to the mRNA decay machinery (PubMed:15687258, PubMed:23644599). Recruits deadenylase CNOT7 (and probably the CCR4-NOT complex) via association with CNOT1, and hence promotes ARE-mediated mRNA deadenylation (PubMed:23644599). Functions also by recruiting components of the cytoplasmic RNA decay machinery to the bound ARE-containing mRNAs (PubMed:11719186, PubMed:12748283, PubMed:15687258, PubMed:16364915). Self regulates by destabilizing its own mRNA (PubMed:15187101). Binds to 3'-UTR ARE of numerous mRNAs and of its own mRNA (PubMed:10330172, PubMed:10751406, PubMed:12115244, PubMed:15187101, PubMed:15634918, PubMed:17030620, PubMed:16702957, PubMed:19188452, PubMed:20702587, PubMed:20221403, PubMed:21775632, PubMed:25815583). Plays a role in anti-inflammatory responses; suppresses tumor necrosis factor (TNF)-alpha production by stimulating ARE-mediated TNF-alpha mRNA decay and several other inflammatory ARE-containing mRNAs in interferon (IFN)- and/or lipopolysaccharide (LPS)-induced macrophages (By similarity). Plays also a role in the regulation of dendritic cell maturation at the post-transcriptional level, and hence operates as part of a negative feedback loop to limit the inflammatory response (PubMed:18367721). Promotes ARE-mediated mRNA decay of hypoxia-inducible factor HIF1A mRNA during the response of endothelial cells to hypoxia (PubMed:21775632). Positively regulates early adipogenesis of preadipocytes by promoting ARE-mediated mRNA decay of immediate early genes (IEGs) (By similarity). Negatively regulates hematopoietic/erythroid cell differentiation by promoting ARE-mediated mRNA decay of the transcription factor STAT5B mRNA (PubMed:20702587). Plays a role in maintaining skeletal muscle satellite cell quiescence by promoting ARE-mediated mRNA decay of the myogenic determination factor MYOD1 mRNA (By similarity). Associates also with and regulates the expression of non-ARE-containing target mRNAs at the post-transcriptional level, such as MHC class I mRNAs (PubMed:18367721). Participates in association with argonaute RISC catalytic components in the ARE-mediated mRNA decay mechanism; assists microRNA (miRNA) targeting ARE-containing mRNAs (PubMed:15766526). May also play a role in the regulation of cytoplasmic mRNA decapping; enhances decapping of ARE-containing RNAs, in vitro (PubMed:16364915). Involved in the delivery of target ARE-mRNAs to processing bodies (PBs) (PubMed:17369404). In addition to its cytosolic mRNA-decay function, affects nuclear pre-mRNA processing (By similarity). Negatively regulates nuclear poly(A)-binding protein PABPN1-stimulated polyadenylation activity on ARE-containing pre-mRNA during LPS-stimulated macrophages (By similarity). Also involved in the regulation of stress granule (SG) and P-body (PB) formation and fusion (By similarity). Plays a role in the regulation of keratinocyte proliferation, differentiation and apoptosis (PubMed:27182009). Plays a role as a tumor suppressor by inhibiting cell proliferation in breast cancer cells (PubMed:26926077).
a. 贴壁培养细胞收集
去除贴壁细胞的培养液,用PBS、NS或无血清培养基清洗1次,低速离心,弃上清,留取沉淀。
b. 悬浮培养细胞收集
速离心悬浮细胞,弃上清,收集沉淀。手指轻弹细胞,使其松散。
c. 组织样本收集
把组织剪切成细小的碎片,越小越好。取液氮或超低温冰箱中冷冻30min以上的组织,迅速用液氮研磨,研磨过程尽量控制在1~2min之内,以减少蛋白的降解。
(2)总蛋白提取
a. 细胞/组织裂解
将装有细胞沉淀或组织碎片的容器完全插入冰中。细胞沉淀按照1mL裂解液/107个细胞(1个T75培养瓶细胞量)的比例加入相应体积的裂解液(细胞量足够时都加入3mL,不足时根据细胞量计算),裂解20min,每隔5min将离心管置于涡旋振荡仪上震荡10s。组织碎片按照0.5mL 裂解液/100mg组织向匀浆器中加入蛋白裂解液,每3min研磨一次,重复5次,使组织尽量碾碎。(裂解液中根据需要选择添加或不添加蛋白酶抑制剂)。
b. 离心
把裂解好的样品配平后,置于预冷的高速冷冻离心机中,12000 rpm,15min。
c. 蛋白变性
完成离心后,上清即为蛋白提取液。吸取少量蛋白提取液做蛋白浓度测定。向剩余的蛋白提取液的离心管中加入1/5上清体积的5×Loading Buffer(最终工作液为1X),待干式恒温器温度升至95℃后,将1.5mL离心管插入加热孔中,95℃加热变性10min,待液体完全冷却后置于-20℃保存。
(3)蛋白浓度测定(BCA法)
a. BCA工作液的配置
根据样品数量,按50体积BCA试剂A加入1体积BCA试剂B(50:1)配置适量BCA工作液,充分混匀。BCA工作液室温24h内稳定。
b. 标准品测定
取10μl蛋白标准品(5mg/ml BSA)稀释至50μl,使终浓度为1mg/ml。稀释后的蛋白标准品可以-20℃长期保存。此标准品溶液的稀释液可使用去离子水或1*PBS。将标准品按0、1、2、4、8、12、16、20μl加入到96孔板中,加稀释液补足到20μl(见附表)。加适当体积样品到96孔板的样品孔中,如果样本不足20μl,需加稀释液补足到20μl。请注意记录样品体积。各孔加入200μl BCA工作液,37℃放置20-30min。用酶标仪测定A562,或540-595nm之间的其他波长吸光度。根据标准曲线和使用的样品体积计算出样品的蛋白浓度。
a. Western Transfer Buffer至少提前2h (即开始电泳后)放入-20℃冰箱预冷,但注意避免结冰。
b. 根据胶体大小,将Filter Paper及Nitrocellulose membrane剪裁至合适尺寸。
c. 目的蛋白>20KD选择0.45μm NC膜/PVDF膜;目的蛋白<20KD选择0.2μmNC膜或PVDF膜,选择完毕后将NC膜放在Western Transfer Buffer中浸泡备用,注意如使用的是PVDF膜需先放入甲醇中浸泡5-10min,再放入Western Transfer Buffer中浸泡备用。
(2)裂解液&洗杂液:Cell lysis buffer for IP (without inhibitors)
(3)蛋白酶抑制剂
(4)封闭液:含 3% BSA 的 1X PBS
(5)1×PBS 缓冲液
(6)5×loding buffer(使用时用去离子水稀释至工作浓度即可)
(7)Control IgG (AC005/ AC011/AC034)
二、实验步骤
1、样本处理
(1)贴壁培养细胞
a. 取裂解液室温溶解混匀,根据需要选择添加或不添加蛋白酶抑制剂。
b. 去除贴壁细胞的培养液,用PBS、NS或无血清培养基清洗1次,低速离心,弃上清,留取沉淀。
c. 按照6孔板每孔加入100~200μl裂解液的比例,加入裂解液。移液器轻轻吹打,使裂解液和细胞充分接触。通常裂解液作用于细胞1~5s内,细胞会被裂解。
d. 1000~12000g,离心3~5min(如果用冷冻离心机4℃效果更佳),取上清。
(2)悬浮培养细胞
a. 取裂解液室温溶解混匀,根据需要选择添加或不添加蛋白酶抑制剂。
b. 速离心悬浮细胞,弃上清,收集沉淀。
c. 手指轻弹细胞,使其松散。按照6孔板每孔加入100~200μl裂解液的比例,加入NP-40裂解液。通常6孔板每孔加入100~200μl裂解液已经足够,但如果细胞密度非常高可以适当加大裂解液的用量150~200μl,再用手指轻弹以充分裂解细胞。充分裂解后应无明显沉淀。
d. 1000~12000g,离心3~5min(如果用冷冻离心机4℃效果更佳),取上清。
(3)组织样本
a. 取裂解液室温溶解混匀,根据需要选择添加或不添加蛋白酶抑制剂。
b. 把组织剪切成细小的碎片,越小越好。
c. 取液氮或超低温冰箱中冷冻30min以上的组织,迅速用液氮研磨,研磨过程尽量控制在1~2min之内,以减少蛋白的降解。
d. 按照每20mg组织加入100~200μl裂解液的比例,加入含有PMSF的裂解液。冰上或4℃裂解30-60min。(步骤3、4也可采用以下过程:按照每20mg组织加入100~200μl裂解液的比例加入NP-40裂解液。用玻璃匀浆器或组织研磨器匀浆,直至充分裂解,过程尽量控制在1~2min之内,以减少蛋白的降解。)
e. 按照每20mg组织加入100~200μl裂解液的比例,加入裂解液。
f. 1000~12000g,4℃离心10~15min(如无低温离心机,室温下离心也可),取上清。
2、磁珠预处理
(1)将rProtein A/G Plus MaqPoly Beads颠倒或漩涡混匀,翻转瓶身发现底部无黑色沉淀即可。
(2)取30μl rProtein A/G Plus MaqPoly Beads至新的EP管中,放在磁分离器上,待溶液澄清后,用移液器吸弃保护液。
(3)将EP管从磁分离器上取下来,加入1ml Cell lysis buffer for IP (without inhibitors),混匀,放置在磁分离器上,收集磁珠,用移液器吸弃洗杂液,重复2次。