Western blot analysis of IGF2BP1/IMP1 expressed in Mouse brain,Rat kidney,HepG2 using IGF2BP1/IMP1 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 IGF2BP1/IMP1 expressed in Mouse brain,Rat kidney,HepG2 using IGF2BP1/IMP1 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.
This gene encodes a member of the insulin-like growth factor 2 mRNA-binding protein family. The protein encoded by this gene contains four K homology domains and two RNA recognition motifs. It functions by binding to the mRNAs of certain genes, including insulin-like growth factor 2, beta-actin and beta-transducin repeat-containing protein, and regulating their translation. Two transcript variants encoding different isoforms have been found for this gene.
IMP1,ZBP1,CRDBP,IMP-1,CRD-BP,VICKZ1,IGF2BP1/IMP1 Rabbit pAb,IGF2BP1,Coding region determinant-binding protein,IGF-II mRNA-binding protein 1,VICKZ family member 1,Zipcode-binding protein 1
组织表达
Mainly expressed in the embryo, including in fetal liver, fetal lung, fetal kidney, fetal thymus (at protein level). Also expressed follicles of ovary, as well as in gonocytes of testis, spermatogonia, semen, oocytes and placenta (at protein level). Expressed in various cancers, including testis and lung cancers (at protein level), as well as kidney, prostate and trachea cancers.
功能
RNA-binding factor that recruits target transcripts to cytoplasmic protein-RNA complexes (mRNPs). This transcript 'caging' into mRNPs allows mRNA transport and transient storage. It also modulates the rate and location at which target transcripts encounter the translational apparatus and shields them from endonuclease attacks or microRNA-mediated degradation. Plays a direct role in the transport and translation of transcripts required for axonal regeneration in adult sensory neurons (By similarity). Regulates localized beta-actin/ACTB mRNA translation, a crucial process for cell polarity, cell migration and neurite outgrowth. Co-transcriptionally associates with the ACTB mRNA in the nucleus. This binding involves a conserved 54-nucleotide element in the ACTB mRNA 3'-UTR, known as the 'zipcode'. The RNP thus formed is exported to the cytoplasm, binds to a motor protein and is transported along the cytoskeleton to the cell periphery. During transport, prevents ACTB mRNA from being translated into protein. When the RNP complex reaches its destination near the plasma membrane, IGF2BP1 is phosphorylated. This releases the mRNA, allowing ribosomal 40S and 60S subunits to assemble and initiate ACTB protein synthesis. Monomeric ACTB then assembles into the subcortical actin cytoskeleton (By similarity). During neuronal development, key regulator of neurite outgrowth, growth cone guidance and neuronal cell migration, presumably through the spatiotemporal fine tuning of protein synthesis, such as that of ACTB (By similarity). May regulate mRNA transport to activated synapses (By similarity). Binds to and stabilizes ABCB1/MDR-1 mRNA (By similarity). During interstinal wound repair, interacts with and stabilizes PTGS2 transcript. PTGS2 mRNA stabilization may be crucial for colonic mucosal wound healing (By similarity). Binds to the 3'-UTR of IGF2 mRNA by a mechanism of cooperative and sequential dimerization and regulates IGF2 mRNA subcellular localization and translation. Binds to MYC mRNA, in the coding region instability determinant (CRD) of the open reading frame (ORF), hence prevents MYC cleavage by endonucleases and possibly microRNA targeting to MYC-CRD. Binds to the 3'-UTR of CD44 mRNA and stabilizes it, hence promotes cell adhesion and invadopodia formation in cancer cells. Binds to the oncofetal H19 transcript and to the neuron-specific TAU mRNA and regulates their localizations. Binds to and stabilizes BTRC/FBW1A mRNA. Binds to the adenine-rich autoregulatory sequence (ARS) located in PABPC1 mRNA and represses its translation. PABPC1 mRNA-binding is stimulated by PABPC1 protein. Prevents BTRC/FBW1A mRNA degradation by disrupting microRNA-dependent interaction with AGO2. Promotes the directed movement of tumor-derived cells by fine-tuning intracellular signaling networks. Binds to MAPK4 3'-UTR and inhibits its translation. Interacts with PTEN transcript open reading frame (ORF) and prevents mRNA decay. This combined action on MAPK4 (down-regulation) and PTEN (up-regulation) antagonizes HSPB1 phosphorylation, consequently it prevents G-actin sequestration by phosphorylated HSPB1, allowing F-actin polymerization. Hence enhances the velocity of cell migration and stimulates directed cell migration by PTEN-modulated polarization. Interacts with Hepatitis C virus (HCV) 5'-UTR and 3'-UTR and specifically enhances translation at the HCV IRES, but not 5'-cap-dependent translation, possibly by recruiting eIF3. Interacts with HIV-1 GAG protein and blocks the formation of infectious HIV-1 particles. Reduces HIV-1 assembly by inhibiting viral RNA packaging, as well as assembly and processing of GAG protein on cellular membranes. During cellular stress, such as oxidative stress or heat shock, stabilizes target mRNAs that are recruited to stress granules, including CD44, IGF2, MAPK4, MYC, PTEN, RAPGEF2 and RPS6KA5 transcripts.
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。
