Cervantes-Chávez José A, Kronberg Florencia, Passeron Susana, Ruiz-Herrera José
Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del IPN., Irapuato, Gto., Mexico.
Fungal Genet Biol. 2009 May;46(5):390-9. doi: 10.1016/j.fgb.2009.02.005. Epub 2009 Feb 26.
Previous studies on the dimorphic transition of Yarrowia lipolytica suggested opposite roles for MAPK and PKA pathways in this phenomenon. To obtain conclusive evidences for these opposite roles we isolated and disrupted the unique gene encoding the Pka catalytic subunit (TPK1). TPK1 was regulated only at the post-transcriptional level, with Pka activity increasing during yeast-like growth. tpk1 null mutants were viable and without growth defects, but more sensitive to different stress conditions. Deltatpk1 mutants were mating-deficient, and grew constitutively in the mycelial form, whereas Deltaste11 (Mapkkk-less)/Deltatpk1 double mutants grew in the yeast form, indicating that this is the default growth pattern of the fungus. Our data confirm that MAPK and PKA pathways operate in opposition during the dimorphic behavior of Y. lipolytica, but synergic in mating. These data stress the idea that in different fungi both signal transduction systems may operate distinctly or even be antagonistic or synergic in the coordination of cell responses to different stimuli.
先前关于解脂耶氏酵母双态转变的研究表明，丝裂原活化蛋白激酶（MAPK）和蛋白激酶A（PKA）信号通路在这一现象中发挥着相反的作用。为了获得支持这些相反作用的确凿证据，我们分离并破坏了编码Pka催化亚基（TPK1）的唯一基因。TPK1仅在转录后水平受到调控，在酵母样生长过程中Pka活性增加。tpk1基因缺失突变体能够存活且无生长缺陷，但对不同胁迫条件更为敏感。Δtpk1突变体存在交配缺陷，且持续以菌丝体形式生长，而Δste11（无丝裂原活化蛋白激酶激酶激酶）/Δtpk1双突变体以酵母形式生长，这表明这是该真菌的默认生长模式。我们的数据证实，在解脂耶氏酵母的双态行为中，MAPK和PKA信号通路发挥相反作用，但在交配过程中协同作用。这些数据强调了这样一种观点，即在不同真菌中，这两种信号转导系统在协调细胞对不同刺激的反应时可能有不同的作用方式，甚至可能相互拮抗或协同。
