Gamma synuclein belongs to the synuclein family which are believed to be involve in the pathogenesis of neurodegenerative diseases. High levels of gamma synuclein have been identified in andvanced breast carcinomas suggesting a correlation between gamma synuclein overexpression and breast tumor development. Gama synuclein plays a role in neurofilament network integrity. May be involved in modulating axonal architecture during development and in the adult. In vitro, increases the susceptibility of neurofilament-H to calcium-dependent proteases. May also function in modulating the keratin network in skin. Activates the MAPK and Elk-1 signal transduction pathway. SUBUNIT: May be a centrosome-associated protein. SUBCELLULAR LOCATION: Cytoplasm; perinuclear region. Centrosome. Spindle. Associated with centrosomes in several interphase cells. In mitotic cells, localized to the poles of the spindle. TISSUE SPECIFICITY: Highly expressed in brain, particularly in the substantia nigra. Also expressed in the corpus callosum, heart, skeletal muscle, ovary, testis, colon and spleen. Weak expression in pancreas, kidney and lung. PTM: Phosphorylated. Phosphorylation by GRK5 appears to occur on residues distinct from the residue phosphorylated by other kinases. DISEASE: Brain iron accumulation type 1 (NBIA1, also called Hallervorden-Spatz syndrome), a rare neuroaxonal dystrophy, is histologically characterized by axonal spheroids, iron deposition, Lewy body (LB)-like intraneuronal inclusions, glial inclusions and neurofibrillary tangles. SNCG is found in spheroids but not in inclusions.