Nuclear translocation of the calcium-binding protein ALG-2 induced by the RNA-binding protein RBM22

• Published in: Biochimica et biophysica acta Vol. 1763; no. 11; pp. 1335 - 1343
• Main Authors: Montaville, P., Dai, Y., Cheung, C.Y., Giller, K., Becker, S., Michalak, M., Webb, S.E., Miller, A.L., Krebs, J.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-11-2006
• Subjects: Active Transport, Cell Nucleus; ALG-2, RBM22; Amino Acid Sequence; Animals; Apoptosis Regulatory Proteins - analysis; Apoptosis Regulatory Proteins - genetics; Apoptosis Regulatory Proteins - metabolism; Ca 2+-binding protein; Calcium Signaling; Calcium-Binding Proteins - analysis; Calcium-Binding Proteins - genetics; Calcium-Binding Proteins - metabolism; Cell Nucleus - chemistry; Cell Nucleus - metabolism; Confocal microscopy; Humans; Mice; Molecular Sequence Data; NIH 3T3 Cells; RNA-binding protein; RNA-Binding Proteins - analysis; RNA-Binding Proteins - genetics; RNA-Binding Proteins - metabolism; Transfection; Two-Hybrid System Techniques; Zebrafish - embryology; Zebrafish - metabolism; Zebrafish development; ALG-2, RBM22; Ca 2+-binding protein; Confocal microscopy; RNA-binding protein; Zebrafish development
• ISSN: 0167-4889; 0006-3002; 1879-2596
• DOI: 10.1016/j.bbamcr.2006.09.003

By yeast two-hybrid screening using the calcium-binding protein ALG-2 as bait a new target of ALG-2 was identified, the RNA-binding protein RBM22. In order to confirm these interactions
in vivo we prepared fluorescent constructs by using the monomeric red fluorescent protein to label ALG-2 and the enhanced green fluorescent protein to label RBM22. Confocal microscopy of NIH 3T3 cells transfected with either ALG-2 or RBM22 expression constructs encoding fluorescent fusion proteins alone revealed that the majority of ALG-2 was localized in the cytoplasm whereas RBM22 was located in the nucleus. When cells were co-transfected with expression vectors encoding both fusion proteins ALG-2 was found in the nucleus indicating that RBM22 which can shuttle between the cytoplasm and the nucleus may play a role in nuclear translocation of ALG-2. Using zebrafish as a model mRNA homologues of ALG-2 and RBM22 were microinjected into the blastodisc-yolk margin of zebrafish embryos at the 1-cell stage followed by monitoring the fusion proteins during development of the zebrafish. Hereby, we observed that ALG-2 alone evenly distributed within the cell, whereas in the presence of RBM22 the two proteins co-localized within the nucleus. More than 95% of the two proteins co-localized within the same area in the nucleus suggesting a functional interaction between the Ca
2+-signaling protein ALG-2 and the RNA-binding protein RBM22.