CDNF is a secreted neurotrophic factor that contains 8 conserved cysteine residues, much like its relative MANF. CDNF and its structural homolog MANF each contain an N-terminal saposin-like lipid binding domain and a carboxyl-terminal domain, which is not homologous to previously characterized protein structures. CDNF is expressed in several tissues, including the embryonic and postnatal brains of mice, as well as the heart, skeletal muscle, and testis. It has been shown to promote survival, growth and function of dopamine specific neurons. CDNF and MANF can prevent 6-OHDA induced degeneration of dopaminergic neurons by triggering survival pathways in a rat experimental model of Parkinson disease.

CDNF is a secreted neurotrophic factor that contains 8 conserved cysteine residues, much like its relative MANF. CDNF and its structural homolog MANF each contain an N-terminal saposin-like lipid binding domain and a carboxyl-terminal domain, which is not homologous to previously characterized protein structures. CDNF is expressed in several tissues, including the embryonic and postnatal brains of mice, as well as the heart, skeletal muscle, and testis. It has been shown to promote survival, growth and function of dopamine specific neurons. CDNF and MANF can prevent 6-OHDA induced degeneration of dopaminergic neurons by triggering survival pathways in a rat experimental model of Parkinson disease.

Ciliary neurotrophic factor (CNTF) is a polypeptide hormone whose actions appear to be restricted to the nervous system where it promotes neurotransmitter synthesis and neurite outgrowth in certain neuronal populations. It was initially identified as a trophic factor for embryonic chick ciliary parasympathetic neurons in culture. The protein is also a potent survival factor for neurons and oligodendrocytes and may be relevant in reducing tissue destruction during inflammatory attacks. In addition, CNTF is useful for treatment of motor neuron disease and it could reduce food intake without causing hunger or stress. CNTF is structurally related to IL6, IL11, LIF, and OSM. All of these four helix bundle cytokines share gp130 as a signal-transducing subunit in their receptor complexes.

Glial cell-derived neurotrophic factor (GDNF) is a small protein that promotes the survival of various neuronal subpopulations in both the central as well as the peripheral nervous systems at different stages of their development. GDNF is a founding member of the GDNF family of ligands (GFL) and has been shown to interact with GDNF family receptor alpha 1 (GDNFA1) and GDNFA2. Rat GDNF exists as a homodimer and contains seven conserved cysteine residues, one of which (Cys 101) is used for inter-chain disulfide bridging while the others are involved in intramolecular ring formation known as the cystine knot configuration.

Glia maturation factor beta is an actin-binding protein that shows sequence similarity to the ADF/ cofilin family. It is expressed in the cytosol and on the cell surface of astrocytes and interacts with target receptors in a juxtacrine manner. GMFB is involved in the differentiation of glial cells and neurons. It stimulates axon regeneration and proliferation of astroblasts, and inhibits proliferation of tumors. It also reversibly inhibits proliferation of neuronal and non-neuronal neoplastic cells by arresting the cell cycle in the G0/G1 phase. It is suggested that GMFB acts an intracellular regulator of signal pathways. Analysis of crystallography and NMR reveals structural differences between murine and human ADF-H domains.

Persephin (PSPN) belongs to the GDNF ligand subfamily of the TGF-beta superfamily. The amino acid sequence of PSPN exhibits significant homology to GDNF. PSPN is synthesized throughout the nervous system and presumably originates from both astroglial cells and neurons. It promotes the survival and growth of mesencephalic dopaminergic and motor neurons. It also plays a role in kidney development by promoting ureteric bud branching. PSPN binds to a receptor complex consisting of Ret tyrosine kinase and GFR-alpha-4.