Pom152 limits NPC dilation in Schizosaccharomyces pombe

Abstract

The nuclear pore complex (NPC) bridges the inner and outer nuclear membrane and consists of a nuclear and a cytoplasmic ring that flank an inner ring. The inner ring is surrounded by a luminal ring predicted to be composed of the transmembrane nucleoporin pom152. The NPC is highly dynamic; previous research showed how nuclear envelope tension regulates constriction and dilation of the complex. Which nucleoporins are involved in regulating the NPC diameter has yet to be discovered. During dilation, the luminal pom152 ring changes drastically, forming a ring encircling the membrane closely and potentially regulating the NPC diameter. Here, I used cryo-electron microscopy (cryo-ET) and live cell fluorescence microscopy to investigate the effect of pom152∆ on NPC diameter and nuclear volume during hypo-osmotic shock in cellulo. My findings show the limiting effect of pom152 on the NPC diameter and imply a nuclear leakage of hypo-osmotically shocked pom152∆ cells.