NKAIN1

Model summary

A single-pass membrane-associated regulator that binds ATPase complexes and modulates their assembly and activity at the cell surface. By anchoring to the plasma membrane and engaging pump assemblies, it fine-tunes ion transport systems and supports biogenesis of multisubunit proton pumps. This scaffolding role coordinates pump stabilization and trafficking, thereby coupling surface ion-handling pathways with lysosomal acidification machinery.

Predicted Gene Ontology terms

1. 01

   I begin with the InterPro architecture: IPR008516 (Na,K-Atpase Interacting protein family) spans residues 1–206 and covers the entire polypeptide.

   A single full-length family signature without embedded catalytic domains indicates a non-enzymatic membrane-associated regulator that binds and modulates P-type ATPases. The family designation explicitly ties the protein to Na+/K+-ATPase systems, and the compact length is consistent with a single-pass membrane scaffold that stabilizes or tunes pump assemblies.

2. 02

   This architecture causally supports ATPase association as the core molecular function.

   The absence of catalytic motifs and the presence of a dedicated ATPase-interacting family domain argue that the protein binds and regulates ATPase complexes rather than performing transport itself. This directly aligns with GO:0051117 ATPase binding as the molecular function: the domain composition and membrane anchoring create a high-affinity platform for ATPase engagement.

3. 03

   From this binding function, I infer the biological process by considering what assembly control accomplishes.

   The explicit link to V-type ATPase biogenesis is captured by GO:0070070 proton-transporting V-type ATPase complex assembly. A membrane scaffold that binds ATPases can chaperone or coordinate assembly of multisubunit proton pumps, especially during endo-lysosomal trafficking. The same binding chemistry that targets Na+/K+-ATPase can be repurposed to shepherd V-ATPase assembly steps, providing a mechanistic bridge between pump assemblies in different pathways.

4. 04

   Cellular localization follows from both the membrane-anchored architecture and pump biology.

   The protein is annotated as a single-pass membrane component and is positioned at the cell surface, which matches GO:0005886 plasma membrane. A single transmembrane helix typically tethers regulatory scaffolds to the membrane while exposing interaction surfaces to the cytosol; this arrangement situates the protein at the plasma membrane where Na+/K+-ATPase operates and where signaling assemblies form.

5. 05

   Integrating these lines, I propose a mechanism: a membrane-tethered ATPase-binding scaffold that modulates Na+/K+-ATPase activity and trafficking while also promoting V-ATPase assembly.

   By stabilizing pump complexes and coordinating their assembly and turnover, the protein can tune ion homeostasis and membrane excitability and, in parallel, support lysosomal acidification through V-ATPase biogenesis. Likely interaction partners include Na+/K+-ATPase alpha/beta subunits at the plasma membrane and cytosolic assembly factors for V-ATPase; transient contacts with trafficking adaptors would facilitate pump recycling and endo-lysosomal routing.