Kowalski L R, Kondo K, Inouye M
Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey at Rutgers, Piscataway, USA.
Mol Microbiol. 1995 Jan;15(2):341-53. doi: 10.1111/j.1365-2958.1995.tb02248.x.
TIP1 is the first known cold-shock- and heat-shock-induced gene in Saccharomyces cerevislae. Here it is demonstrated that a TIP1 homologue, TIR1, which had been previously cloned as SRP1 (serine-rich protein), is strongly induced by a downshift in growth temperature from 30 to 10 degrees C. We further cloned TIR2, which is transcribed at a low basal level but is increased strongly by cold shock and, to a lesser extent, by heat shock. The predicted protein sequence of TIR2 demonstrates remarkable homology to TIR1 (72.2%) and is also homologous with TIP1 (49%). TIP1, TIR1 and TIR2 are rich in both serine and alanine residues and each contains serine-rich tandem repeats. The proteins contain putative N-terminal signal peptides as well as hydrophobic C-terminal sequences, indicating that the proteins may be membrane bound. The predicted protein sequences are also consistent with extensive O-mannosylation as well as glycosyl-phosphatidyl inositol (GPI) membrane anchoring. Cell fractionation analysis as well as studies using a yeast strain that is conditionally deficient in glycosylation demonstrate that TIP1 is a heavily modified membrane-associated protein. Single, double combinations and triple mutants were created and none demonstrated any obvious phenotype, indicating that this family of genes is not essential for normal growth.
TIP1是酿酒酵母中首个已知的冷休克和热休克诱导基因。本文证明，先前作为SRP1（富含丝氨酸蛋白）克隆的TIP1同源物TIR1，在生长温度从30℃降至10℃时会被强烈诱导。我们进一步克隆了TIR2，它在基础水平转录较低，但冷休克会使其强烈增加，热休克在较小程度上也会使其增加。TIR2的预测蛋白序列与TIR1具有显著同源性（72.2%），并且也与TIP1同源（49%）。TIP1、TIR1和TIR2富含丝氨酸和丙氨酸残基，且每个都包含富含丝氨酸的串联重复序列。这些蛋白质含有推定的N端信号肽以及疏水的C端序列，表明这些蛋白质可能是膜结合的。预测的蛋白序列也与广泛的O-甘露糖基化以及糖基磷脂酰肌醇（GPI）膜锚定一致。细胞分级分离分析以及使用糖基化条件性缺陷酵母菌株的研究表明，TIP1是一种高度修饰的膜相关蛋白。构建了单突变体、双突变体组合和三突变体，均未表现出任何明显的表型，表明该基因家族对于正常生长并非必需。
