Protooncogene c-fos is rapidly and transiently activated in response to a wide variety of stimuli and is therefore under a strict control of a great number of signal-transmitting systems. At the same time, the c-fos gene promoter has a complex organization since it determines the basic functional properties of this gene that are pertinent in cell differentiation and proliferation as well as in multiple stress responses. Interaction of external factors with the cell surface is accompanied by specific activation of intracellular processes promoting the interaction of definite transcription factors with the c-fos gene promoter. Depending on its mode, this interaction may trigger a wide range of signal-transmitting systems, in which membrane components (receptors, G- and Ras-proteins, adaptor proteins, tyrosine specific protein kinases) and cytoplasmic protein kinases (PKC, PKA, MAR-kinase cascade components) play a crucial role. Despite the linear mode of some of those pathways of signal transduction, many of their components interact with the concomitant factors which complicates signal transduction network but expands the potentialities of fine regulation of the c-fos gene.