Cortical aPKC kinase activity distinguishes neural stem cells from progenitor cells by ensuring asymmetric segregation of Numb.
Cortical aPKC kinase activity distinguishes neural stem cells from progenitor cells by ensuring asymmetric segregation of Numb.
复制标题
DOI：
10.1016/j.ydbio.2012.02.027
复制
发表时间：
2012-05-01
影响因子：
2.7
通讯作者：
Lee CY
中科院分区：
文献类型：
--
作者：
Haenfler JM;Kuang C;Lee CY
在不对称干细胞分裂过程中，细胞皮层的极化将命运决定因素不平等地靶向到兄弟姐妹中，导致干细胞再生并产生发育潜力有限的祖细胞。在果蝇幼虫大脑的有丝分裂神经干细胞（神经母细胞）中，极性蛋白 Lethal (2) 巨型幼虫 (Lgl) 和非典型蛋白激酶 C (aPKC) 之间的拮抗相互作用通过调节命运决定因素的不对称分离确保子代神经母细胞的自我更新和祖细胞的生成。在缺乏 lgl 功能的情况下，皮质 aPKC 激酶活性升高会扰乱包括 Numb 在内的命运决定因素的不平等分配，并在幼虫大脑中诱导多余的神经母细胞。然而，aPKC 功能的增强是否会通过灭活 Numb 来触发过量神经母细胞的形成仍存在争议。为了研究皮质 aPKC 功能的增加如何诱导过量神经母细胞的形成，我们分析了 lgl 突变大脑中神经母细胞谱系克隆中细胞的命运。令人惊讶的是，我们的分析表明，lgl 突变大脑中的神经母细胞经历不对称分裂，产生祖细胞，然后恢复为神经母细胞。在 lgl 突变大脑中，Numb 仍定位于有丝分裂神经母细胞的皮层，并且在完成不对称分裂后未能专门分离到祖细胞中。这些结果使我们提出，有丝分裂神经母细胞皮质中 aPKC 功能的升高会降低未来祖细胞中 Numb 的功能。我们发现，含有 3 蛋白 (ACBD3) 结合区的酰基辅酶 A 结合域对于有丝分裂神经母细胞中 Numb 的不对称分离以及抑制 aPKC 功能增强诱导的多余神经母细胞表型至关重要。 Numb 的 ACBD3 结合区包含两个 aPKC 磷酸化位点，即丝氨酸 48 和 52。令人惊讶的是，虽然这两个位点的磷酸化状态直接影响 Numb 在有丝分裂神经母细胞中的不对称分离，但 Numb 的磷酸模拟形式和非磷酸化形式都抑制了皮质 aPKC 功能增强引发的过量神经母细胞的形成。因此，我们提出，皮质 aPKC 激酶活性的精确调节部分通过确保 Numb 不对称分配到未来的祖细胞中来区分兄弟细胞身份，其中 Numb 独立于 aPKC 的调节而保持受限的电位。
During asymmetric stem cell division, polarization of the cell cortex targets fate determinants unequally into the sibling daughters, leading to regeneration of a stem cell and production of a progenitor cell with restricted developmental potential. In mitotic neural stem cells (neuroblasts) in fly larval brains, the antagonistic interaction between the polarity proteins Lethal (2) giant larvae (Lgl) and atypical Protein Kinase C (aPKC) ensures self-renewal of a daughter neuroblast and generation of a progenitor cell by regulating asymmetric segregation of fate determinants. In the absence of lgl function, elevated cortical aPKC kinase activity perturbs unequal partitioning of the fate determinants including Numb and induces supernumerary neuroblasts in larval brains. However, whether increased aPKC function triggers formation of excess neuroblasts by inactivating Numb remains controversial. To investigate how increased cortical aPKC function induces formation of excess neuroblasts, we analyzed the fate of cells in neuroblast lineage clones in lgl mutant brains. Surprisingly, our analyses revealed that neuroblasts in lgl mutant brains undergo asymmetric division to produce progenitor cells, which then revert back into neuroblasts. In lgl mutant brains, Numb remained localized in the cortex of mitotic neuroblasts and failed to segregate exclusively into the progenitor cell following completion of asymmetric division. These results led us to propose that elevated aPKC function in the cortex of mitotic neuroblasts reduces the function of Numb in the future progenitor cells. We identified that the acyl-CoA binding domain containing 3 protein (ACBD3) binding region is essential for asymmetric segregation of Numb in mitotic neuroblasts and suppression of the supernumerary neuroblast phenotype induced by increased aPKC function. The ACBD3 binding region of Numb harbors two aPKC phosphorylation sites, serines 48 and 52. Surprisingly, while the phosphorylation status at these two sites directly impinged on asymmetric segregation of Numb in mitotic neuroblasts, both the phosphomimetic and non-phosphorylatable form of Numb suppressed formation of excess neuroblasts triggered by increased cortical aPKC function. Thus, we propose that precise regulation of cortical aPKC kinase activity distinguishes the sibling cell identity in part by ensuring asymmetric partitioning of Numb into the future progenitor cell where Numb maintains restricted potential independently of regulation by aPKC.
登录
查看更多内容
影响因子：
3.3
作者：
Dho, Sascha E.;Trejo, JoAnn;McGlade, C. Jane
通讯作者：
McGlade, C. Jane
影响因子：
11.8
作者：
Nishimura, Takashi;Kaibuchi, Kozo
通讯作者：
Kaibuchi, Kozo
影响因子：
7.2
作者：
Prehoda, Kenneth E.
通讯作者：
Prehoda, Kenneth E.
影响因子：
64.8
作者：
Betschinger, J;Mechtler, K;Knoblich, JA
通讯作者：
Knoblich, JA
影响因子：
64.8
作者：
Peng, CY;Manning, L;Doe, CQ
通讯作者：
Doe, CQ