Polarized growth and the role of detyrosinated microtubules

丝状真菌的极化生长依赖于肌动蛋白和微管(MT)细胞骨架及其相关的马达蛋白、肌球蛋白、动蛋白和动力蛋白。黄曲霉含有11种不同的激动素。UNCA属于Kinesin-3家族(以前的UNC-104)，负责运输囊泡。令人惊讶的是，依赖UNCA的囊泡运动发生在MTS的一个亚群上。GFP标记的UncArigor修饰单个MT，它在有丝分裂过程中保持完整，而其他胞质MT解聚。观察到的MTS亚群由去甲基化的α-微管蛋白组成。相比之下，Kinesin-1(传统的Kinesin)和Kinesin-7(Kipa)并不显示出对某些MT的偏好。这是丝状真菌中不同MT亚群的第一个例子，也是第一个针对去酪氨酸化MT的Kinesin-3马达的例子。将分析去酪氨酸化的MTS的作用、UNCA结合的特异性和货泡的含量。去酪氨酸化的MTS似乎比酪氨酸化的MTS更稳定，但在MTS稳定后，C端似乎发生了修饰。为了了解这种稳定性，将对MT+末端相关蛋白进行表征。为了理解UNCA在弧菌中的作用，鉴定货物蛋白是至关重要的。将分离囊泡，并用蛋白质组学方法分析其内容。

Polarized growth of filamentous fungi depends on the actin and the microtubule (MT) cytoskeleton along with their associated motor proteins, myosins, kinesins and dynein. A. nidulans contains eleven different kinesins. UncA belongs to the kinesin-3 family (formerly Unc- 104) and transports vesicles. Surprisingly, UncA-dependent vesicle movement occurred along a subpopulation of MTs. GFP labeled UncArigor decorated a single MT, which remained intact during mitosis, while other cytoplasmic MTs were depolymerized. The observed subpopulation of MTs consists of detyrosinated alpha-tubulin. In contrast, kinesin-1 (conventional kinesin) and kinesin-7 (KipA) did not show a preference for certain MTs. This is the first example for different MT subpopulations in filamentous fungi and the first example for the preference of a kinesin-3 motor for detyrosinated MTs. The role of detyrosinated MTs, the specificity for UncA binding and the content of cargo vesicles will be analyzed. Detyrosinated MTs appear to be more stable than tyrosinated ones, but the C-terminal end appears to be modified after MTs are stabilized. To understand this stabilization, MT plus end-associated proteins will be characterized. For the understandind of the role of UncA in A. nidulans, it is essential to identify cargo proteins. Vesicles will be isolated and their content analyzed in a proteome approach.