Another goal is to understand distribution of a sorting isozyme between the cytosol and the nucleus. The nucleus has several subcompartments yet little is known about how nuclear substructures are generated or maintained. Location of Trm1p. The protein is located on the inner nuclear membrane. The natural distribution and function of sorting isozymes provides a powerful tool to identify gene products important to protein delivery.
Most proteins have a single destination.
In contrast, sorting isozymes have multiple destinations and their distribution is balanced. Cells display phenotypes when the balance is altered and these phenotypes can be used to identify mutations affecting distribution.