Regulation of yeast glycogen metabolism and sporulation by Glc7p protein phosphatase.
Regulation of yeast glycogen metabolism and sporulation by Glc7p protein phosphatase.
复制标题
Glc7p 蛋白磷酸酶调节酵母糖原代谢和孢子形成。
DOI：
10.1093/genetics/149.1.57
复制
发表时间：
1998
期刊：
影响因子：
3.3
通讯作者：
Cannon,JF
中科院分区：
文献类型：
--
作者：
Ramaswamy,NT;Li,L;Khalil,M;Cannon,JF
Glc7p 是来自酿酒酵母的必需丝氨酸/苏氨酸 1 型蛋白磷酸酶 (PP1)，它在许多过程中发挥作用，包括细胞周期进程、孢子形成、糖原积累、翻译起始和葡萄糖抑制。 PP1 酶的两个特点是氨基酸序列高度保守以及催化亚基与各种非催化调节亚基的关联。我们测试了以下假设：PP1 序列保守性是每个 PP1 残基在多种分子间相互作用中发挥作用的结果。对 24 个 Glc7 突变体（主要通过其糖原积累性状分离）的分析表明，每个突变的 Glc7p 残基都会改变许多非催化亚基亲和力，并在不同程度上赋予未选择的孢子形成性状。此外，定量分析表明，Glc7p 对糖原结合非催化亚基 Gac1p 的亲和力并不是决定 glc7 突变体糖原积累的唯一参数。 Sds22p 是一种 Glc7p 非催化亚基，对于有丝分裂生长至关重要。令人惊讶的是，几种突变的 Glc7p 蛋白对 Sds22p 具有不可检测的亲和力，但生长明显正常。 glc7 二倍体孢子形成的表征表明，Glc7p 至少具有两个减数分裂作用。在孢子形成最差的 glc7 突变体中检测不到减数分裂前的 DNA 合成。在检查的glc7二倍体中，减数分裂诱导物IME1的表达与glc7二倍体孢子形成频率成正比。此外，IME1 超表达不能抑制 glc7 孢子形成性状。 Glc7p/Gip1p 全酶可能参与减数分裂或孢子包装的完成，因为当一些 glc7 二倍体孢子形成时，减数分裂二分体占主导地位。
Glc7p is an essential serine/threonine type 1 protein phosphatase (PP1) from the yeast Saccharomyces cerevisiae, which has a role in many processes including cell cycle progression, sporulation, glycogen accumulation, translation initiation, and glucose repression. Two hallmarks of PP1 enzymes are very high amino acid sequence conservation and association of the catalytic subunit with a variety of noncatalytic, regulatory subunits. We tested the hypothesis that PP1 sequence conservation was the result of each PP1 residue playing a role in multiple intermolecular interactions. Analysis of 24 glc7 mutants, isolated primarily by their glycogen accumulation traits, revealed that every mutated Glc7p residue altered many noncatalytic subunit affinities and conferred unselected sporulation traits to various degrees. Furthermore, quantitative analysis showed that Glc7p affinity for the glycogen-binding noncatalytic subunit Gac1p was not the only parameter that determines the glycogen accumulation by a glc7 mutant. Sds22p is one Glc7p noncatalytic subunit that is essential for mitotic growth. Surprisingly, several mutant Glc7p proteins had undetectable affinity for Sds22p, yet grew apparently normally. The characterization of glc7 diploid sporulation revealed that Glc7p has at least two meiotic roles. Premeiotic DNA synthesis was undetectable in glc7 mutants with the poorest sporulation. In the glc7 diploids examined, expression of the meiotic inducer IME1 was proportional to the glc7 diploid sporulation frequency. Moreover, IME1 hyperexpression could not suppress glc7 sporulation traits. The Glc7p/Gip1p holoenzyme may participate in completion of meiotic divisions or spore packaging because meiotic dyads predominate when some glc7 diploids sporulate.