The Arabidopsis STE20/Hippo kinase SIK1 regulates polarity independently of PIN proteins
The Arabidopsis STE20/Hippo kinase SIK1 regulates polarity independently of PIN proteins
复制标题
拟南芥 STE20/Hippo 激酶 SIK1 独立于 PIN 蛋白调节极性
DOI：
10.1016/j.bbrc.2021.02.083
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发表时间：
2021
影响因子：
3.1
通讯作者：
Gong Qingqiu
中科院分区：
文献类型：
--
作者：
Zhang Pingping;Yu Xiulian;Bai Jing;Gong Qingqiu
极性是生命的一个特征。在高等植物中，非自主极性在很大程度上由生长素指导，生长素是驱动其自身极化流的形态发生素，极性生长素运输（PAT），以指导模式化事件，如叶序性和向性。质膜定位的PIN形成（PIN）生长素外排载体是PAT的限速因子。在酵母和后生动物中，STE 20激酶是细胞极性的关键参与者。我们以前的特点是SIK 1作为一个STE 20/河马的直向同源物在拟南芥，并证实其功能有丝分裂出口和器官生长。在这里，我们探讨了SIK 1，生长素，PIN和极性之间的可能联系。sik 1在主根伸长和侧根出现方面对外源生长素更敏感。RNA-Seq显示生长素生物合成基因的表达减少，并诱导生长素通量载体insik 1的表达。然而，正常组织和亚细胞定位模式的PIN 1和PIN 2观察insik 1。黑暗诱导的PIN 2液泡降解也在1中表现正常。在sik 1 pin 1双突变体中观察到加性表型，表明SIK 1不直接调节PIN 1。因此，sik 1的极性缺陷不太可能由PIN介导，并等待未来的探索。
Polarity is a feature of life. In higher plants, non-autonomous polarity is largely directed by auxin, the morphogen that drives its own polarized flow, Polar Auxin Transport (PAT), to guide patterning events such as phyllotaxis and tropism. The plasma membrane-localized PIN-FORMED (PIN) auxin efflux carriers are rate-limiting factors in PAT. In yeasts and metazoans, the STE20 kinases are key players in cell polarity. We had previously characterized SIK1 as a STE20/Hippo orthologue in Arabidopsis and confirmed its function in mitotic exit and organ growth. Here we explore the possible link between SIK1, auxin, PIN, and polarity. Abnormal phyllotaxis and gravitropism were observed insik1.sik1was more sensitive to exogenous auxin in primary root elongation and lateral root emergence. RNA-Seq revealed reduced expression in auxin biosynthesis genes and induced expression of auxin flux carriers insik1. However, normal tissue- and sub-cellular localization patterns of PIN1 and PIN2 were observed insik1. The dark-induced vacuolar degradation of PIN2 also appeared normal insik1. An additive phenotype was observed in thesik1 pin1double mutant, indicating that SIK1 does not directly regulate PIN1. The polarity defects ofsik1are hence unlikely mediated by PINs and await future exploration.