PDF(Pubmed)
Abstract：
Depending on their phosphorylation status, derivatives of phosphatidylinositol play important roles in vesicle identity, recognition and intracellular trafficking processes. In eukaryotic cells, phosphatidylinositol-4 phosphate pools generated by specific kinases are key determinants of the conventional secretion pathways. Earlier work in yeast has classified phosphatidylinositol-4 kinases in two types, Stt4p and Pik1p belonging to type III and Lsb6p to type II, with distinct cellular localizations and functions. Eurotiomycetes appear to lack Pik1p homologues. In Aspergillus nidulans, unlike homologues in other fungi, AnLsb6 is associated to late Golgi membranes and when heterologously overexpressed, it compensates for the thermosensitive phenotype in a Saccharomyces cerevisiae pik1 mutant, whereas its depletion leads to disorganization of Golgi-associated PHOSBP-labelled membranes, that tend to aggregate dependent on functional Rab5 GTPases. Evidence provided herein, indicates that the single type II phosphatidylinositol-4 kinase AnLsb6 is the main contributor for decorating secretory vesicles with relevant phosphatidylinositol-phosphate species, which navigate essential cargoes following the route of apical polarization via endocytic recycling.
摘要：
根据它们的磷酸化状态，磷脂酰肌醇衍生物在囊泡身份中起重要作用，识别和细胞内贩运过程。在真核细胞中,由特定激酶产生的磷脂酰肌醇-4磷酸池是常规分泌途径的关键决定因素。酵母的早期工作将磷脂酰肌醇4激酶分为两种类型，Stt4p和Pik1p属于III型，Lsb6p属于II型，具有不同的细胞定位和功能。欧洲真菌似乎缺乏Pik1p同源物。在构巢曲霉中，与其他真菌的同源物不同，AnLsb6与晚期高尔基膜相关，当异源过度表达时，它补偿了酿酒酵母pik1突变体的热敏表型，而它的消耗导致高尔基相关的PHOSBP标记的膜的解体，倾向于聚集依赖于功能性Rab5GTP酶。此处提供的证据，表明单一II型磷脂酰肌醇-4激酶AnLsb6是用相关的磷脂酰肌醇-磷酸物种装饰分泌囊泡的主要贡献者，它们通过胞吞再循环沿着心尖极化的路线导航基本货物。
