Han Sang Won, Alonso Jose M, Rojas-Pierce Marcela
Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina, United States of America.
PLoS One. 2015 Apr 27;10(4):e0125621. doi: 10.1371/journal.pone.0125621. eCollection 2015.
Vacuoles are dynamic compartments with constant fluctuations and transient structures such as trans-vacuolar strands and bulbs. Bulbs are highly dynamic spherical structures inside vacuoles that are formed by multiple layers of membranes and are continuous with the main tonoplast. We recently carried out a screen for mutants with abnormal trafficking to the vacuole or aberrant vacuole morphology. We characterized regulator of bulb biogenesis1-1 (rbb1-1), a mutant in Arabidopsis that contains increased numbers of bulbs when compared to the parental control. rbb1-1 mutants also contain fewer transvacuolar strands than the parental control, and we propose the hypothesis that the formation of transvacuolar strands and bulbs is functionally related. We propose that the bulbs may function transiently to accommodate membranes and proteins when transvacuolar strands fail to elongate. We show that RBB1 corresponds to a very large protein of unknown function that is specific to plants, is present in the cytosol, and may associate with cellular membranes. RBB1 is involved in the regulation of vacuole morphology and may be involved in the establishment or stability of trans-vacuolar strands and bulbs.
液泡是具有不断波动和瞬态结构（如跨液泡链和液泡球）的动态区室。液泡球是液泡内高度动态的球形结构，由多层膜形成，并与主要的液泡膜连续。我们最近对液泡运输异常或液泡形态异常的突变体进行了筛选。我们鉴定了液泡球生物发生调节因子1-1（rbb1-1），这是拟南芥中的一个突变体，与亲本对照相比，其液泡球数量增加。rbb1-1突变体的跨液泡链也比亲本对照少，我们提出跨液泡链和液泡球的形成在功能上相关的假说。我们认为，当跨液泡链无法伸长时，液泡球可能短暂地发挥作用以容纳膜和蛋白质。我们表明，RBB1对应于一种功能未知的非常大的植物特异性蛋白质，存在于细胞质中，并可能与细胞膜相关联。RBB1参与液泡形态的调节，可能参与跨液泡链和液泡球的形成或稳定性维持。
