hnRNPs H, H ' and F behave differently with respect to posttranslational cleavage and subcellular localization

hnRNPs H, H' and F belong to a subfamily of the hnRNPs sharing a high degre e of sequence identity, Eukaryotic expression and specific C-terminal antib odies were used to demonstrate great variation in the intracellular fate of the proteins. hnRNPs it and H' become posttranslational cleaved into C-ter minal 35 kDa proteins (H-C, H'(C)) and possibly into N-terminal 22 kDa prot eins. No detectable cleavage was observed for hnRNP F, hnRNP H/H' is almost exclusively localized to the nucleus of many cell types while hnRNP F vari es from a predominant nuclear localization in some cells to a predominant c ytoplasmic localization in other cells. The different fates may reflect dif ferences in functional roles that so far only have included nuclear functio ns. The presence of significant quantities of hnRNP F in the cytoplasm of m any cells indicates that it also may have a functional role here, (C), 1999 Federation of European Biochemical Societies.