NEMP2

Model summary

A multi-pass membrane scaffold that resides in the endoplasmic reticulum and nuclear envelope, where it organizes higher-order assemblies that shape and stabilize the nuclear envelope. By mediating multivalent protein interactions within the ER–nuclear envelope continuum, it coordinates membrane remodeling and envelope integrity, thereby supporting nuclear membrane organization and the broader architecture of the nucleus.

Predicted Gene Ontology terms

1. 01

   I begin with the InterPro architecture: IPR019358 (NEMP family, residues 3–416) spans essentially the entire polypeptide, indicating a dedicated membrane-associated scaffold rather than a modular enzyme.

   NEMP-family proteins are characterized by multiple transmembrane segments that embed in the endoplasmic reticulum and contiguous nuclear envelope, where they assemble higher-order complexes. The single, full-length family signature argues that the membrane-anchored core drives oligomerization and partner recruitment, which causally establishes a primary molecular role in multivalent protein binding (GO:0005515).

2. 02

   A membrane-embedded scaffold that nucleates assemblies at the ER–nuclear envelope continuum will directly influence nuclear membrane organization.

   By stabilizing and positioning membrane-associated complexes, the NEMP architecture provides the physical framework that shapes and maintains the double membrane of the nucleus and its continuity with the ER. This causal linkage from membrane scaffolding to envelope shaping maps to nuclear membrane organization (GO:0071763).

3. 03

   The cellular context follows from the same architecture.

   Multi-pass topology and the NEMP-family identity place the protein in the endoplasmic reticulum (GO:0005783), with enrichment at the contiguous nuclear envelope. The experimentally observed nuclear envelope localization and multi-pass nature are consistent with an ER-resident, envelope-spanning scaffold that traffics and accumulates at the inner/outer nuclear membrane interface.

4. 04

   Mechanistically, the membrane-integrated NEMP scaffold likely binds cytosolic and membrane partners to coordinate envelope morphogenesis and stability.

   It plausibly engages lamina-associated complexes and membrane-remodeling modules. I hypothesize interactions with lamina and envelope adaptors (LMNA/LMNB1), membrane-anchored nuclear-envelope proteins (EMD/emerin), and ER–nuclear envelope tethers and curvature modules (VAPB, RTN3/RTN4). These assemblies would couple membrane curvature, lipid composition, and cytoskeletal anchoring to maintain nuclear envelope integrity and regulate its dynamics during the cell cycle and differentiation.