Yeast Ulpl, an Smt3-Specific Protease, Associates with Nucleoporins

Yeast Smt3 is a ubiquitin-like protein similar to the mammalian SUMO-1. Cde3, a septin component, is known to be modified by Smt3. The level of this modification was affected by Smt3-specific protease mutation ulpl-ts or overexpression of ULPl. By two-hybrid screening, we isolated 5 UIP (Ulpl interacting protein) genes. UIP1 was identical to NUP42 encoding a component of the nuclear pore complex (NPC). Glel, another NPC-associating component, also interacted with Ulpl in the two-hybrid system and co-immunoprecipitation experiment. Thus Ulpl associates with nucleoporins and may interact with septin rings in the telophase