action potential adaptor protein adrenal gland autocrine signalling autoimmunity bacteria bistability camp camp dependent pathway caenorhabditis elegans cancer cardiac muscle cardiac pacemaker cell cycle cell division cell membrane cell nucleus chloride circulatory system communication complex system complex systems cytoplasm differentiation disease egfr embryo emergent endocrine system endocrinology entrez epidermal growth factor epinephrine epithelium estrogen estrogen receptor gaba gap junction gastrointestinal tract gene general transcription factor gonad hedgehog signaling pathway homeostasis hormone immune system intracellular receptor ion channel jak-stat signaling pathway juxtacrine signalling kinase lipid bilayer lipid signaling mammal mating of yeast medical subject headings neural network neuroendocrine neuron neurotransmitter norepinephrine notch signaling pathway ovary paracrine signalling peptide phosphate phosphorylation physiology preinitiation complex proceedings of the national academy of sciences protease protein-protein interaction protein kinase quorum sensing saccharomyces cerevisiae second messenger system semiotics signal transduction stem cell systems biology tgf beta signaling pathway transcription factor ii d transcription factor transmembrane receptor uterus wnt signaling pathway