STIL 是来自花粉管的一种特殊分子，可特异性去磷酸化花粉受体激酶 LePRK2，并在体外刺激花粉管生长。
STIL, a peculiar molecule from styles, specifically dephosphorylates the pollen receptor kinase LePRK2 and stimulates pollen tube growth in vitro.
机构信息
Instituto de Ingeniería Genética y Biología Molecular, CONICET, Buenos Aires, Argentina.
出版信息
BMC Plant Biol. 2010 Feb 22;10:33. doi: 10.1186/1471-2229-10-33.
BACKGROUND
LePRK1 and LePRK2 are two pollen receptor kinases localized to the plasma membrane, where they are present in a high molecular weight complex (LePRK complex). LePRK2 is phosphorylated in mature and germinated pollen, but is dephosphorylated when pollen membranes are incubated with tomato or tobacco style extracts.
RESULTS
Here we show that LePRK2 dephosphorylation is mediated by a heat-, acid-, base-, DTT- and protease-resistant component from tobacco styles. Using LePRK2 phosphorylation as a tracking assay for purification, style exudates were subjected to chloroform extraction, anionic exchange, and C18 reverse-phase chromatography columns. We finally obtained a single ~3,550 Da compound (as determined by UV-MALDI-TOF MS) that we named STIL (for Style Interactor for LePRKs). STIL increased pollen tube lengths of in vitro germinated pollen in a dose-dependent manner.
CONCLUSION
We propose that the LePRK complex perceives STIL, resulting in LePRK2 dephosphorylation and an increase in pollen tube growth.
背景
LePRK1 和 LePRK2 是两种定位于质膜的花粉受体激酶，在那里它们存在于高分子量复合物（LePRK 复合物）中。LePRK2 在成熟和萌发的花粉中被磷酸化，但当花粉膜与番茄或烟草柱头提取物孵育时，其磷酸化被去磷酸化。
结果
在这里，我们表明 LePRK2 的去磷酸化是由烟草柱头中的一种热、酸、碱、DTT 和蛋白酶抗性成分介导的。使用 LePRK2 磷酸化作为纯化的跟踪测定，柱头分泌物经过氯仿提取、阴离子交换和 C18 反相色谱柱。我们最终获得了一种单一的~3550 Da 化合物（通过 UV-MALDI-TOF MS 确定），我们将其命名为 STIL（LePRKs 的柱头相互作用因子）。STIL 以剂量依赖的方式增加体外萌发花粉的花粉管长度。
结论
我们提出 LePRK 复合物感知到 STIL，导致 LePRK2 去磷酸化和花粉管生长增加。
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