# Defining the mechanisms of nuclear pore complex assembly in fission yeast

> **NIH NIH F32** · STOWERS INSTITUTE FOR MEDICAL RESEARCH · 2020 · $65,310

## Abstract

PROJECT SUMMARY
Nuclear pore complexes (NPCs) span the inner and outer nuclear membranes and allow for the regulated
transport of macromolecules across the nuclear envelope. In addition, NPCs have important transport
independent functions, including influencing nuclear envelope dynamics and integrity, contributing to
chromosomal organization and regulating gene expression. Many features of NPC structure and function are
conserved throughout eukaryotes; however, NPC number, distribution, composition and function can change
dramatically during development and in response to environmental signals. Additionally, increased NPC density
has been observed in human diseases including cancer. Work in numerous organisms has identified the
conserved transmembrane nucleoporin Ndc1 as a key factor required for NPC assembly and insertion into the
nuclear envelope. However, the exact mechanism by which NPC insertion occurs remains unclear. Additionally,
attempts to dissect the role of Ndc1 and other putative insertion factors at NPCs in yeast have been complicated
by their dual functions in the insertion of the yeast spindle pole body. To overcome these issues, we have
developed innovative genetic and imaging approaches to characterize proteins that interact with the fission yeast
Ndc1 ortholog, Cut11. Using high-throughput membrane yeast-two hybrid screens, we identified novel Cut11
interacting proteins involved in lipid metabolism and membrane organization that are conserved in vertebrates
and have determined how these interactions are modulated by Cut11 mutations. We have also developed 3D
structured illumination microscopy and image analysis tools to allow us to visualize and quantify NPCs in vivo.
Importantly, this approach allows for determining NPC composition while maintaining single NPC resolution, and
has revealed a region with heterogenous NPC composition near the spindle pole body. We will utilize this
powerful imaging platform to determine whether the newly identified Cut11 interacting proteins localize to NPCs
and have a function in NPC assembly and insertion. We will also examine the molecular mechanisms that
regulate the localization of the conserved nuclear envelope protein Tts1 to the NPCs and clarify its role in NPC
assembly and distribution. Last, we will define the composition of NPCs in the region near the spindle pole body
and determine how this specialized pool of NPCs is established and maintained. These studies will expand our
understanding of how NPC assembly is regulated and will provide valuable insight into novel proteins with
potentially conserved functions in NPC assembly from yeast to mammals.

## Key facts

- **NIH application ID:** 9909195
- **Project number:** 1F32GM133096-01A1
- **Recipient organization:** STOWERS INSTITUTE FOR MEDICAL RESEARCH
- **Principal Investigator:** Joseph M Varberg
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $65,310
- **Award type:** 1
- **Project period:** 2020-06-05 → 2021-09-04

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9909195

## Citation

> US National Institutes of Health, RePORTER application 9909195, Defining the mechanisms of nuclear pore complex assembly in fission yeast (1F32GM133096-01A1). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/9909195. Licensed CC0.

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