MYOSIN II STRUCTURE AND FUNCTION IN YEAST

这个项目的长期目标是了解类型的功能 II肌球蛋白受到调节。 整个细胞骨架肌球蛋白超家族 根据它们的运动神经之间的序列相似性 结构域（切尼等人，，1993年）。 五种细胞骨架肌球蛋白已被 在酿酒酵母中鉴定。有三个代表性的类 迄今 虽然在高尔基体后囊泡运输中起着重要作用， 已经证明了酵母V型肌球蛋白Myo2 p（约翰斯顿等人，1991, Govindan等人，1995），其他酵母肌球蛋白如 I型肌球蛋白Myo3p和Myo5p（Goodson等，1994年），第二类 V肌球蛋白，Myo4p（Lillie和Brown，1994）尚不清楚。 酵母II型 肌球蛋白Myo1p似乎对胞质分裂很重要（Watts等，1987年）。 有证据表明肌球蛋白功能之间存在冗余，这可以解释 大多数肌球蛋白基因敲除突变的非致死性。 一个最近 已鉴定的驱动蛋白样马达蛋白Smy1p已被证明是 肌球蛋白Myo1p和My02p在功能上是冗余的，这表明 存在具有类似功能的其他类型的马达蛋白（Brown pers.通信，和Lillie和Brown，1994年分别）。 为了实现我们长期以来 为了达到这一目的，有必要鉴定Myo1p的冗余基因产物。 这些基因的鉴定将使开发适当的 缺失菌株，在其中表达和应用体内功能测试， 突变的重组MY01基因。 这些研究也将扩大我们的 了解II型肌球蛋白和其他蛋白之间的相互作用类型 细胞蛋白质 这项建议的具体目标是：1）进行基因筛选 为了鉴定MyO1的合成致死突变（SL）， 表征和突变编码功能上 与Myo1p冗余。 2)作为目标#1的长期扩展，多副本 将寻找my01合成致死表型（my01，SL）的抑制子 来鉴定可以拯救合成致死表型的基因产物。 这种方法已成功地用于另一种马达蛋白基因， Lillie and Brown（1994）. 3)我们将探讨 Myo1p与正常细胞几丁质酶定位及功能的关系 （Cts1p），以测试在my01突变体中观察到的胞质分裂延迟是否 反映了Myo1p在细胞内转运组分中的作用 是细胞分裂过程中细胞壁代谢所必需的。 4)培养 学生在研究导致研究生学位的生物医学 以理工科为重

The long term goal of this project to understand how the functions of type II myosin are regulated. The entire superfamily of cytoskeletal myosins have been classified based on sequence similarities among their motor domains (Cheney et al.,, 1993). Five cytoskeletal myosins have been identified in Saccharomyces cerevisiae. with three representative classes to date. Although an essential role in post-Golgi vesicle transport has been demonstrated for a yeast type V myosin, Myo2p (Johnston et al., 1991, Govindan et al., 1995), the functions of other yeast myosins such as the type I myosins, Myo3p and Myo5p (Goodson et al., 1994), and a second type V myosin, Myo4p (Lillie and Brown, 1994) are not clear. The yeast type II myosin, Myo1p appears to be important for cytokinesis (Watts et al., 1987). There is evidence for redundancy among myosin functions which may explain th non-lethality of most myosin gene knockout mutations. A recently identified kinesin-like motor protein, Smy1p, has been shown to be functionally redundant with both myosins Myo1p and My02p which suggests that other classes of motor proteins with similar functions exist (Brown pers. comm., and Lillie and Brown, 1994 respectively). To achieve our long term goal, it is necessary to identify gene products redundant with Myo1p. Identification of these genes will allow the development appropriate deletion strains in which to express and apply functional tests in vivo for mutated recombinant MY01 genes. These studies will also expand our understanding of the type of interactions between type II myosins and other cellular proteins. The specific aims of this proposal are: 1) To carry out a genetic screen to identify synthetic lethal mutations (sl's) of myo1 in order to identify, characterize and mutate the genes encoding protein which are functionally redundant with Myo1p. 2) As a long term extension of aim #1, multi-copy suppressors of the my01 synthetic lethal phenotype (my01,sl) will be sought to identify gene products that can rescue the synthetic lethal phenotypes. This approach has been used successfully for another motor protein gene by lillie and Brown (1994). 3) We will explore the possible correlation between Myo1p and normal cellular localization and function of chitinase (Cts1p) to test whether the delay in cytokinesis observed in my01 mutants reflects a role for Myo1p in the intracellular transport of components required for cell wall metabolism during cell division. 4) To train students in research leading to graduate degrees in the biomedical sciences.