Pigment epithelium-derived factor: neurotrophic activity and identification as a member of the serine protease inhibitor gene family.
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Steele FR, Chader GJ, Johnson LV, Tombran-Tink J
Pigment epithelium-derived factor: neurotrophic activity and identification as a member of the serine protease inhibitor gene family.
Proc Natl Acad Sci U S A. 1993 Feb 15;90(4):1526-30.
- PubMed ID
- 8434014 [ View in PubMed]
- Abstract
Cultured pigment epithelial cells of the fetal human retina secrete a protein, pigment epithelium-derived factor (PEDF), that induces a neuronal phenotype in cultured human retinoblastoma cells. Morphological changes include the induction of an extensive neurite meshwork and the establishment of corona-like cellular aggregates surrounding a central lumen. The differentiated cells also show increases in the expression of neuron-specific enolase and the 200-kDa neurofilament subunit. Amino acid and DNA sequence data demonstrate that PEDF belongs to the serine protease inhibitor (serpin) family. The PEDF gene contains a typical signal-peptide sequence, initiator methionine codon, and polyadenylylation signal and matches the size of other members of the serpin superfamily (e.g., alpha 1-antitrypsin). It lacks homology, however, at the putative serpin reactive center. Thus, PEDF could exert a paracrine effect in the embryonic retina, influencing neuronal differentiation by a mechanism that does not involve classic inhibition of serine protease activity.