BCR(B细胞受体,B cell receptor)是B细胞表面的一种重要膜蛋白复合物,由膜结合型免疫球蛋白(mIg)和信号转导亚基Igα/Igβ(CD79a/CD79b)组成,属于免疫球蛋白超家族(Immunoglobulin Superfamily)。它的核心功能是识别抗原并激活B细胞免疫应答。当BCR结合特定抗原后,通过其胞内段的免疫受体酪氨酸激活基序(ITAMs)传递信号,触发B细胞增殖、分化成浆细胞(分泌抗体)或记忆B细胞。BCR的多样性由V(D)J基因重排(一种基因片段随机组合机制)产生,使机体能识别海量抗原。 若BCR基因发生突变,可能导致功能异常。例如:突变使BCR信号过强(如ITAM磷酸化异常)可能引发自身免疫病(如系统性红斑狼疮);而信号缺陷(如CD79a/b突变)会导致免疫缺陷(如无丙种球蛋白血症)。BCR还与B细胞恶性肿瘤密切相关,例如慢性淋巴细胞白血病(CLL)中BCR信号通路持续激活促进癌细胞存活。 BCR过表达可能引发异常B细胞活化,导致自身抗体产生或淋巴瘤;而低表达会削弱体液免疫,增加感染风险。在基因家族层面,免疫球蛋白超家族的共性包括:含免疫球蛋白样结构域(Ig-like domains,一种保守的β折叠结构)、参与细胞识别或信号传导(如TCR、MHC分子等)。 此外,BCR-ABL融合基因(费城染色体导致)是慢性髓性白血病(CML)的标志,其酪氨酸激酶活性失控,但此“BCR”指断裂点簇区(breakpoint cluster region),与B细胞受体无关,需注意术语差异。
A reciprocal translocation between chromosomes 22 and 9 produces the Philadelphia chromosome, which is often found in patients with chronic myelogenous leukemia. The chromosome 22 breakpoint for this translocation is located within the BCR gene. The translocation produces a fusion protein which is encoded by sequence from both BCR and ABL, the gene at the chromosome 9 breakpoint. Although the BCR-ABL fusion protein has been extensively studied, the function of the normal BCR gene product is not clear. The protein has serine/threonine kinase activity and is a GTPase-activating protein for p21rac. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]
染色体22和9之间的相互易位产生费城染色体,这往往是在慢性粒细胞性白血病中发现。对于这种易位染色体断点22位于BCR基因内。易位产生被序列从两个BCR和ABL,在9号染色体断点的基因所编码的融合蛋白。虽然BCR-ABL融合蛋白已被广泛研究,正常bcr基因产物的功能尚不清楚。该蛋白质具有丝氨酸/苏氨酸激酶活性,并且是p21rac GTP酶激活蛋白。已发现该基因编码不同亚型的两个转录变异体。 [由RefSeq的,2008年7月提供]
BCR基因(以及对应的蛋白质)的细胞分布位置:
BCR基因的本体(GO)信息:
| 名称 |
|---|
| 5200 Pathways in cancer [PATH:hsa05200] |
| 5220 Chronic myeloid leukemia [PATH:hsa05220] |
| 名称 |
|---|
| Disease |
| Diseases of signal transduction |
| FGFR1 mutant receptor activation |
| Rho GTPase cycle |
| Signal Transduction |
| Signaling by FGFR in disease |
| Signaling by FGFR1 fusion mutants |
| Signaling by FGFR1 in disease |
| Signaling by FGFR1 mutants |
| Signaling by Rho GTPases |
| 疾病名称 | 关系值 | NofPmids | NofSnps | 来源 |
| Myeloid Leukemia, Chronic | 0.39556717 | 514 | 3 | BeFree_CTD_human_GAD_LHGDN_ORPHANET |
| Blast Phase | 0.144158327 | 89 | 2 | BeFree_CTD_human |
| Precursor Cell Lymphoblastic Leukemia Lymphoma | 0.140649445 | 58 | 0 | BeFree_CTD_human_LHGDN |
| Myeloproliferative disease | 0.128153188 | 21 | 2 | BeFree_CTD_human_LHGDN |
| Neoplasms, Experimental | 0.12 | 1 | 0 | CTD_human |
| Chromosome 22q11.2 Deletion Syndrome, Distal | 0.12 | 0 | 0 | ORPHANET |
| Necrosis | 0.12 | 1 | 0 | CTD_human |
| LEUKEMIA, ACUTE LYMPHOBLASTIC, SUSCEPTIBILITY TO, 3 | 0.12 | 0 | 0 | ORPHANET |
| leukemia | 0.051753097 | 121 | 1 | BeFree_GAD_LHGDN |
| Leukemia, Myelocytic, Acute | 0.027978376 | 85 | 0 | BeFree_LHGDN |
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