Growthfactor

Growth factors are signaling proteins that regulate cellular processes such as proliferation, differentiation, survival, and migration. They act by binding to specific cell-surface receptors, including receptor tyrosine kinases, serine/threonine kinase receptors, and cytokine receptors, triggering intracellular signalling cascades such as MAPK/ERK, PI3K/AKT, and JAK/STAT. These pathways modulate gene expression and cell behavior, often operating in autocrine, paracrine, or endocrine modes and exhibiting redundancy or synergy among factors.

Prominent growth factor families include the epidermal growth factor (EGF) family (EGF, ERBB receptors), the transforming growth factor beta (TGF-β) family, the platelet-derived growth factor (PDGF) family, the vascular endothelial growth factor (VEGF) family, the fibroblast growth factor (FGF) family, hepatocyte growth factor (HGF), insulin-like growth factors (IGF), and nerve growth factors (NGF). Receptors and downstream targets vary by family, enabling diverse cellular responses.

Growth factors are essential for embryonic development, tissue repair and wound healing, angiogenesis, neurogenesis, and metabolic regulation. They influence stem cell maintenance and differentiation and can modulate immune activity. Effects are highly context-dependent, shaped by receptor expression, tissue environment, and combination with other signals.

Dysregulation of growth factor signalling is associated with diseases such as cancer, fibrosis, and inflammatory disorders. Therapeutically, growth factors can promote healing (for example, PDGF and FGF in wounds; bone morphogenetic proteins in orthopedics) or be targeted by drugs (EGFR, VEGF, or FGFR inhibitors) in cancer. Delivery methods include recombinant proteins, gene therapy, and controlled-release formulations.

In research, growth factors support the expansion and maintenance of cells, including embryonic stem cells and induced pluripotent stem cells, and are used to study development and tissue engineering.