Pleiotrophin (PTN)

Pleiotrophin (PTN) is a secreted heparin-binding growth factor and cytokine with a molecular weight of 18 kDa, encoded by the human *PTN* gene[2]. It is structurally related to midkine and functions in cellular proliferation, differentiation, and survival, especially during embryonic development of the nervous system and in processes such as neurite outgrowth, synaptic plasticity, and angiogenesis[2][3]. PTN is expressed in both neural and non-neural tissues and re-expressed during pathology, notably in tumor cells where it promotes tumor growth and angiogenesis[2]. PTN signals through multiple cell surface receptors including RPTPζ, ALK, N-syndecan, LRP, and integrin ανβ3, triggering downstream signaling pathways associated with the extracellular matrix[3]. It plays important roles in neurodevelopment, neuroregeneration after injury, and modulation of memory-related pathways in the hippocampus, but its overexpression can support tumor progression and pathological angiogenesis[2][3].

Other names

Heparin-binding brain mitogenHeparin-binding growth factor 8Heparin-binding growth-associated moleculeHeparin-binding neurite outgrowth-promoting factorNeurite growth-promoting factor 1Heparin affinity regulatory peptideHARPHB-GAMHBNFHBGF-8HBGF8HBNF-1NEGF1OSF-1Osteoblast-specific factor 1

Inhibition or activation of cell proliferation and survival pathways through interaction with receptor protein tyrosine phosphatase ζ (RPTPζ), Anaplastic lymphoma kinase (ALK), N-syndecan, integrin ανβ3, and low-density lipoprotein receptor-related protein (LRP) pathways; influences ERK, PI3K/AKT, STAT5, and other downstream signaling cascades[3].