Abstract
Synucleins are small, highly conserved proteins in vertebrates, especially abundant in neurons and typically enriched in presynaptic terminals. α‐Synuclein protein and a fragment of it, called NAC, have been found in association with pathological lesions of neurodegenerative diseases. Recently, mutations in a α‐synuclein gene have been reported in families susceptible to an inherited form of Parkinson's diseases. In addition, α‐synuclein has been implicated in the pathophysiology of other neurodegenerative diseases, including Alzheimer's disease and multiple system atrophy. Far less is known about other members of the synuclein family, β‐ and γ‐synucleins. γ‐synuclein is up‐regulated in several types of cancer and may affect the integrity of the neurofilament network, while its bovine ortholog, synoretin, activates the Elk‐1 signal transduction pathway. In this paper, we present data about the localization and properties of human and bovine γ‐synuclein in several neuronal and non‐neuronal cell cultures derived from ocular tissues. We show that γ‐synuclein is present in the perinuclear area and is localized to centrosomes in several types of human interphase cells and in bovine retinal pigment epithelium. In mitotic cells, γ‐synuclein staining is localized to the poles of the spindle. Further, overexpression of synoretin in retinoblastoma cells up‐regulates MAPK and Elk‐1. These results support the view that γ‐synuclein is a centrosome protein that may be involved in signal transduction pathways. Cell Motil. Cytoskeleton 49:218–228, 2001. © 2001 Wiley‐Liss, Inc.