Instituto de Ingeniería Genética y Biología Molecular INGEBI - Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Buenos Aires, Argentina.
Plant Physiol Biochem. 2012 Apr;53:40-5. doi: 10.1016/j.plaphy.2012.01.008. Epub 2012 Jan 14.
LePRK1 and LePRK2 are two pollen-specific receptor-like kinases from Solanum lycopersicum that are involved in signaling during pollen-pistil communication. Previously, we showed that both proteins interact in pollen and when expressed in yeast. We also showed that pollen tube length was regulated by phosphorylation of specific residues in the juxtamembrane domain of LePRK2. To determine the domains responsible for the interaction between LePRK1 and LePRK2, we constructed a series of deletions, expressed them in yeast and determined their association by co-immunoprecipitation assays. We show that deletions containing extracellular domains of LePRK1 and LePRK2 were glycosylated in yeast and were sufficient for interaction with the corresponding full-length receptor. The juxtamembrane domain of LePRK1 was sufficient for its interaction with LePRK2, whereas LePRK2 required its kinase domain for interaction with LePRK1. These findings suggest a role for the juxtamembrane domain of LePRK2 in mediating intracellular dimerization and thus receptor kinase phosphorylation.
LePRK1 和 LePRK2 是来自番茄的两种花粉特异性受体样激酶，它们参与花粉-柱头通讯过程中的信号转导。之前，我们表明这两种蛋白在花粉中相互作用，并且在酵母中表达时也是如此。我们还表明，LePRK2 跨膜区特定残基的磷酸化调节花粉管的长度。为了确定 LePRK1 和 LePRK2 之间相互作用的结构域，我们构建了一系列缺失体，在酵母中表达并通过共免疫沉淀实验确定它们的关联。我们表明，包含 LePRK1 和 LePRK2 胞外结构域的缺失体能在酵母中发生糖基化，足以与相应的全长受体相互作用。LePRK1 的跨膜区足以与其与 LePRK2 的相互作用，而 LePRK2 则需要其激酶结构域与 LePRK1 相互作用。这些发现表明 LePRK2 跨膜区在介导细胞内二聚化和受体激酶磷酸化中起作用。
