Influence of Different Stress Conditions on the Subcellular Distribution of ALG-2, RBM22 and hSlu7

Ca²⁺ and calcium binding proteins are one of the key regulators of many cellular processes. ALG-2, is a highly conserved calcium binding protein. Recently we showed (1) that ALG-2 is interacting with RBM22, a highly conserved spliceosomal protein, by transfecting NIH 3T3 cells with expression vectors encoding either ALG2-mRFP or RBM22-EGFP, or both using confocal microscopy. ALG-2 is predominantly located in the cytoplasm whereas RBM22 is a nuclear protein. In sharp contrast, when NIH 3T3 cells expressed both proteins a significant amount of ALG2-mRFP co-localized with RBM22-EGFP within the nucleus indicating that in the presence of RBM22-EGFP ALG2-mRFP translocated to the nucleus. hSlu7, another spliceosomal protein which is also known to interact with RBM22, has been shown to translocate to the cytoplasm under cellular stress conditions thereby influencing its spliceosomal properties (2). Here we present data which provide evidence not only that RBM22 differs from hSlu7 in its cellular localization under stress conditions, but in addition can enhance the cytoplasmic translocation of hSlu7 depending on the stress conditions. We will also present data to show whether stress induced by either heat shock or thapsigargin can influence the nuclear translocation of ALG-2 due to the interaction with RBM22 (3).