磷脂酰肌醇转移蛋白质家族的研究进展  

Current Thoughts on the Phosphatidylinositol Transfer Protein Family

作　　者：祁超[1] 芮斌[1] 

机构地区：[1]中国科学技术大学生命科学学院结构生物学重点实验室,安徽合肥230027

出　　处：《北华大学学报（自然科学版）》2003年第2期105-112,共8页Journal of Beihua University（Natural Science）

基　　金：国家自然科学基金(29701005);中国科学院基础局重大项目(KJ951-A1-504-02)资助

摘　　要：脂类的单体转移是由一类蛋白质来执行的,这组蛋白质把脂类结合到疏水腔,从而使脂类避开了含水环境.其中的这样一组蛋白质是磷脂酰肌醇转移蛋白质家族(PITPs),能结合磷脂酰肌醇和磷脂酰胆碱,把它们从一个膜区转移到另一膜区.PITPs是在单细胞和多细胞组织中发现的,但在细菌中没有发现.在鼠和人类中,人们发现负责脂类转移的PITP结构域有五个蛋白,按照序列分成两类:类型Ⅰ PITPs由两个家族成员α,β构成,它们是小蛋白35 kDa,有一个PITP结构域,可以普遍表达;类型ⅡA PITPs(RdgB αⅠ和Ⅱ)是很大的蛋白质,有另外的结构域,把蛋白质靶向膜,仅能结合脂类,但不能介导转移.类型ⅡB PITP(RdgB β)与类型Ⅰ在大小(38kDa)上相似,也是普遍表达的.类型ⅢPITPs,以Sec14p家族为代表,是在酵母和植物中发现的,但是在序列和结构上与类型Ⅰ和类型ⅡPITPs相似.讨论了PITP蛋白是被动转运蛋白还是调节蛋白,在行使肌醇脂类和膜转换的专门的生物功能时,能否把转运和结舍性质偶连起来.Monomer!c transport of lipids is carried out by a class of proteins that can shield a lipid from the aqueous environment by binding the lipid in a hydrophobic cavity. One such group of proteins is the phosphatidylinositol transfer proteins (PITP) that can bind phosphatidylinositol and phosphatidylcholine and transfer them from one membrane compartment to another. PITPs are found in both unicellular and multicellular organisms but not bacteria. In mice and humans, the PITP domain responsible for lipid transfer is found in five proteins, which can be classified into two classes based on sequence. Class I PITPs comprises two family members, K and L, small 35 kDa proteins with a single PITP domain which are ubiquitously expressed. Class IIA PITPs (RdgBKI and II) are larger proteins possessing additional domains that target the protein to membranes and are only able to bind lipids but not mediate transfer. Finally, Class IIB PITP (RdgBL) is similar to Class I in size(38kDa) and is also ubiquitously expressed. Class III PITPs, exemplified by the Secl4p family,are found in yeast and plants but are unrelated in sequence and structure to Class I and Class II PITPs. In this review we discuss whether PITP proteins are passive transporters or are regulated proteins that are able to couple their transport and binding properties to specific biological functions including inositol lipid signalling and membrane turnover.

关 键 词：磷酸肌醇 膜运输 生长因子 脂类信号 磷脂酰胆碱 磷脂酰肌醇转移蛋白质家族 生物功能 

分 类 号：Q513.3[生物学—生物化学]