To present a satisfactory explanation of the role of Hax-1 transcript binding in the cell, one has to resolve the question of the subcellular location of Hax-1. Hitherto, Hax-1 has been reported to localize predominantly in the mitochondria (35, 36, 37) but it has also been detected in the endoplasmic reticulum (35, 36, 38) , apical membrane (39), lammelipodia (38) and nuclear envelope (35) . In the last case, the presence of Hax-1 in the nuclear envelope was interpreted as a consequence of its association with intracellular membranes (by its putative transmembrane domain), as a continuum of endoplasmic reticulum localization. Our data reveal for the first time, that Hax-1 is associated with the nuclear matrix, which is coherent with its transcript-binding capacity and supports the notion of its role in post-transcriptional regulation.