Figure 2. Model of gonadotropin-regulated testicular RNA helicase (GRTH) action in male germ cells during development. Routes 1 to 6 (in red) represent functions and transit of GRTH protein entry to the nucleous (1), where it binds messages and associates with CRM1 (2), and as an integral component of ribonuclear protein particles (RNPs) exports messages through nuclear pores via the CRM1 pathway to the cytoplasm (3a) and to the chromatoid body (CB) (3b and 4b), either directly (via nuclear pores adjacent to or associated with the CB) (3b) or indirectly (via the cytoplasmic route) (4b). It is phosphorylated at cytoplasmic sites to deliver messages, associates with polyribosomes (4a), and participates in translation. In the CB, messages are potentially regulated via si/mi/pi RNA pathway (RNA storage and degradation) (5a and b). Stored messages are subsequently translated in polyribosomes (4a and 6).