GDF-5 Protein, Human

GDF-5 Protein plays a pivotal role in bone and cartilage formation, intricately regulating chondrogenic tissue differentiation through dual pathways. Firstly, it positively influences chondrogenic tissue differentiation by binding with high affinity to BMPR1B and with lower affinity to BMPR1A, leading to the induction of SMAD1-SMAD5-SMAD8 complex phosphorylation and subsequent SMAD protein signaling transduction. Simultaneously, it negatively regulates chondrogenic differentiation through interaction with NOG. This protein is essential for preventing excessive muscle loss upon denervation, a function mediated by phosphorylated SMAD1/5/8. Additionally, GDF-5 binds bacterial lipopolysaccharide (LPS) and mediates LPS-induced inflammatory responses, including TNF secretion by monocytes. Structurally, it forms homodimers linked by disulfide bonds and interacts with serine proteases HTRA1 and HTRA3. Following LPS binding, GDF-5 may form a complex with CXCR4, HSP90AA1, and HSPA8. Moreover, it interacts with high affinity with NOG to inhibit chondrogenesis and with BMPR1B and BMPR1A to positively regulate chondrocyte differentiation through SMAD-dependent signaling. Additionally, it engages in interactions with FBN1 and FBN2.