A pathophysiology diagram illustrating the JAK-STAT signaling pathway and points of therapeutic inhibition. The process begins at the cell membrane where a cytokine ligand (1) binds to a transmembrane receptor. This triggers Janus Kinases (JAK) to phosphorylate the receptor tails, facilitating the docking and phosphorylation of signal transducer and activator of transcription (STAT) proteins (2). Phosphorylated STATs then dissociate (3) and form an active dimer which translocates into the nucleus (4). Inside the nucleus, the STAT dimer binds to a specific promoter region on the DNA (5), initiating the transcription of cytokine genes (6) and resulting in the extracellular release of cytokines (7). The diagram highlights two pharmacological targets: JAK inhibitors (A), which act near the membrane to prevent phosphorylation; and STAT inhibitors (B), which are shown blocking the translocation of STAT dimers and the subsequent production of pro-inflammatory cytokines, indicated by red 'X' marks. This schematic is utilized to explain the mechanism of action for precision medicine in treating primary immune disorders and inflammatory conditions.

This pathophysiology diagram compares the intracellular signaling pathways of the full-length growth hormone receptor (flGHR) and the exon 3-deleted growth hormone receptor (d3GHR). Both pathways illustrate Growth Hormone (GH) binding to the extracellular domain of the GHR, leading to the recruitment and phosphorylation of Janus kinase 2 (JAK2) in the cytoplasm. Downstream signal transduction involves the activation of SHC, IRS, STAT, PI3K, and MAPK pathways. In the d3GHR variant, the diagram depicts hyperactivation of these signaling cascades, visually indicated by 'burst' icons around the cytoplasmic proteins (STAT, PI3K, IRS, MAPK), multiple phosphorylation markers on JAK2, and red upward arrows. This hyperactivation in the d3GHR pathway is associated with increased sensitivity of the JAK-STAT pathway, resulting in enhanced transcription of GH target genes compared to the standard flGHR isoform. The illustration serves as an educational tool for endocrinology and molecular biology to demonstrate how genetic variations in receptor structure influence hormonal signal intensity and gene expression.

This pathophysiology diagram illustrates the signaling pathways and cellular mechanisms involving Rheumatoid Arthritis Fibroblast-like Synoviocytes (RA-FLS) and their inhibition by Janus kinase (JAK) inhibitors. The central element is an RA-FLS, which promotes several pathogenic processes: secretion of Vascular Endothelial Growth Factor (VEGF), cytokine-induced production of pro-inflammatory mediators and chemokines, and the formation of a multi-layered synovial lining structure. Additionally, the diagram shows a pathway where Focal Adhesion Kinase (FAK) activation leads to increased cell invasion. The educational focus is on the targeted therapeutic effects of specific drugs: Baricitinib is shown inhibiting FAK; Peficitinib is depicted inhibiting both VEGF production and the formation of the multi-layered structure; and both Tofacitinib and Baricitinib are shown inhibiting the secretion of pro-inflammatory mediators. Standard notation is used, with arrows representing stimulation/progression and perpendicular bars representing inhibition. This schematic is designed for medical education regarding the pharmacological management of rheumatoid arthritis at the molecular and cellular level.