PathwayStep4257 PathwayStep4230 PathwayStep4234 PathwayStep4280 PathwayStep4077 Botulinum neurotoxicity HIV Infection Disease Biological processes are captured in Reactome by identifying the molecules (DNA, RNA, protein, small molecules) involved in them and describing the details of their interactions. From this molecular viewpoint, human disease pathways have three mechanistic causes: the inclusion of microbially-expressed proteins, altered functions of human proteins, or changed expression levels of otherwise functionally normal human proteins.<p>The first group encompasses the infectious diseases such as influenza, tuberculosis and HIV infection. The second group involves human proteins modified either by a mutation or by an abnormal post-translational event that produces an aberrant protein with a novel function. Examples include somatic mutations of EGFR and FGFR (epidermal and fibroblast growth factor receptor) genes, which encode constitutively active receptors that signal even in the absence of their ligands, or the somatic mutation of IDH1 (isocitrate dehydrogenase 1) that leads to an enzyme active on 2-oxoglutarate rather than isocitrate, or the abnormal protein aggregations of amyloidosis which lead to diseases such as Alzheimer's.<p>Infectious diseases are represented in Reactome as microbial-human protein interactions and the consequent events. The existence of variant proteins and their association with disease-specific biological processes is represented by inclusion of the modified protein in a new or variant reaction, an extension to the 'normal' pathway. Diseases which result from proteins performing their normal functions but at abnormal rates can also be captured, though less directly. Many mutant alleles encode proteins that retain their normal functions but have abnormal stabilities or catalytic efficiencies, leading to normal reactions that proceed to abnormal extents. The phenotypes of such diseases can be revealed when pathway annotations are combined with expression or rate data from other sources. Reactome Database ID Release 431643685 Reactome, http://www.reactome.org ReactomeREACT_116125 Signaling by EGFR in Cancer Latent infection of Homo sapiens with Mycobacterium tuberculosis Influenza Infection Signaling by FGFR in disease Diabetes pathways Amyloids Mucopolysaccharidoses PI3K/AKT Signaling in Cancer Abnormal metabolism in phenylketonuria PathwayStep3434 PathwayStep3957 PathwayStep3963 PathwayStep3675 PathwayStep3762 PathwayStep3815