Wattiau P, Woestyn S, Cornelis G R
Microbial Pathogenesis Unit, International Institute of Cellular and Molecular Pathology, Brussels, Belgium.
Mol Microbiol. 1996 Apr;20(2):255-62. doi: 10.1111/j.1365-2958.1996.tb02614.x.
Pathogenic yersiniae secrete about a dozen anti-host proteins, the Yops, by a pathway which does not involve cleavage of a classical signal peptide. The Yop secretory apparatus, called Ysc, for Yop secretion, is the archetype of type III secretion systems (which serve for the secretion of virulence proteins by several animal and plant pathogens) and is related to the flagellar assembly apparatus. The Yop secretion signal is N-terminal but has not been defined to date. Apart from the Ysc machinery, secretion of at least four Yops requires cytoplasmic proteins called Syc (for specific Yop chaperone). Each Syc protein binds to its cognate Yop. Unlike most cytoplasmic chaperones, these proteins do not have an ATP-binding domain, and are presumably devoid of ATPase activity. They share a few common properties: an acidic pl, a size in the range of 15-20 kDa, and a putative amphipathic alpha-helix in the C-terminal portion. They were recently shown to have counterparts in other pathogenic bacteria, where they appear to have a similar function.
致病性耶尔森菌通过一种不涉及经典信号肽切割的途径分泌约十二种抗宿主蛋白，即Yop蛋白。用于分泌Yop蛋白的分泌装置称为Ysc，它是III型分泌系统（多种动植物病原体借此分泌毒力蛋白）的原型，与鞭毛组装装置相关。Yop分泌信号位于N端，但迄今为止尚未明确。除了Ysc机制外，至少四种Yop蛋白的分泌还需要称为Syc（特异性Yop伴侣蛋白）的胞质蛋白。每种Syc蛋白都与其对应的Yop蛋白结合。与大多数胞质伴侣蛋白不同，这些蛋白没有ATP结合结构域，可能也没有ATP酶活性。它们具有一些共同特性：酸性pH值、大小在15 - 20 kDa范围内，以及C端部分有一个假定的两亲性α螺旋。最近发现它们在其他致病细菌中也有对应物，且似乎具有类似功能。
