The biogenesis of nuclear pore complexes (NPCs) represents a paradigm for the 
assembly of high-complexity macromolecular structures. So far, only three 
integral pore membrane proteins are known to function redundantly in NPC 
anchoring within the nuclear envelope. Here, we describe the identification and 
functional characterization of Pom33, a novel transmembrane protein dynamically 
associated with budding yeast NPCs. Pom33 becomes critical for yeast viability 
in the absence of a functional Nup84 complex or Ndc1 interaction network, which 
are two core NPC subcomplexes, and associates with the reticulon Rtn1. Moreover, 
POM33 loss of function impairs NPC distribution, a readout for a subset of genes 
required for pore biogenesis, including members of the Nup84 complex and RTN1. 
Consistently, we show that Pom33 is required for normal NPC density in the 
daughter nucleus and for proper NPC biogenesis and/or stability in the absence 
of Nup170. We hypothesize that, by modifying or stabilizing the nuclear 
envelope-NPC interface, Pom33 may contribute to proper distribution and/or 
efficient assembly of nuclear pores.