Male germ cell differentiation signaling events : role of phosphorylation and ubiquitination

The intracellular transduction of exogenous stimuli that trigger a stimulatory or inhibitory (proliferative or differentiative) signal causes a pluripotent stem cell (the spermatogonion) to transform into a highly differentiated, polarized, and motile cell–the spermatozoon. Spermatogenesis is a complicated process that requires the coordinated efforts of germ cells and somatic cells within the tubular structure of the testis. There are various modalities by which this phenomenon occurs. Although the specific molecular transducers can be species-specific, cell -specific or age -specific, the key signal transduction mechanisms are shared by most organisms with sexual reproduction.