biostudies-literatureZhang WDeutsche ForschungsgemeinschaftHeinz Götze Memorial Fellowship877-894https://www.ebi.ac.uk/biostudies/studies/S-EPMC5839787biostudies-literatureUnknown217(3)The paralogous Brr6 and Brl1 are conserved integral membrane proteins of the nuclear envelope (NE) with an unclear role in nuclear pore complex (NPC) biogenesis. Here, we analyzed double-degron mutants of Brr6/Brl1 to understand this function. Depletion of Brr6 and Brl1 caused defects in NPC biogenesis, whereas the already assembled NPCs remained unaffected. This NPC biogenesis defect was not accompanied by a change in lipid composition. However, Brl1 interacted with Ndc1 and Nup188 by immunoprecipitation, and with transmembrane and outer and inner ring NPC components by split yellow fluorescent protein analysis, indicating a direct role in NPC biogenesis. Consistently, we found that Brr6 and Brl1 associated with a subpopulation of NPCs and emerging NPC assembly sites. Moreover, <i>BRL1</iThe Journal of cell biologyBrr6 and Brl1 locate to nuclear pore complex assembly sites to promote their biogenesis.PMC5839787SFB/TRR83Schi 295/5-2Zhang WLuchtenborg CBrugger BRuthnick DSachsenheimer TSchiebel ENeuner AfalseBrr6 and Brl1 locate to nuclear pore complex assembly sites to promote their biogenesis.The paralogous Brr6 and Brl1 are conserved integral membrane proteins of the nuclear envelope (NE) with an unclear role in nuclear pore complex (NPC) biogenesis. Here, we analyzed double-degron mutants of Brr6/Brl1 to understand this function. Depletion of Brr6 and Brl1 caused defects in NPC biogenesis, whereas the already assembled NPCs remained unaffected. This NPC biogenesis defect was not accompanied by a change in lipid composition. However, Brl1 interacted with Ndc1 and Nup188 by immunoprecipitation, and with transmembrane and outer and inner ring NPC components by split yellow fluorescent protein analysis, indicating a direct role in NPC biogenesis. Consistently, we found that Brr6 and Brl1 associated with a subpopulation of NPCs and emerging NPC assembly sites. Moreover, <i>BRL1</i2018-01-01T00:00:00Z2018 Mar2026-05-06T03:45:36.61Z2019-10-30T08:13:39ZS-EPMC58397872943911610.1083/jcb.201706024