Subcellular Localisation of 14‐3‐3 Isoforms in Rat Brain Using Specific Antibodies

Abstract

The 14‐3‐3 protein family, which is present at particularly high concentrations in mammalian brain, is known to be involved in various cellular functions, including protein kinase C regulation and exocytosis. Despite the fact that most of the 14‐3‐3 proteins are cytosolic, a small but significant proportion of 14‐3‐3 in brain is tightly and selectively associated with some membranes. Using a panel of isoform‐specific antisera we find that the ε, η, γ, β, and ζ isoforms are all present in purified synaptic membranes but absent from mitochondrial and myelin membranes. In addition, the η, ε, and γ isoforms but not the β and ζ isoforms are associated with isolated synaptic junctions. When different populations of synaptosomes were fractionated by a nonequilibrium Percoll gradient procedure, the ε and γ isoforms were present and the β and ζ isoforms were absent from the membranes of synaptosomes sedimenting in the more dense parts of the gradient. The finding that these proteins are associated with different populations of synaptic membranes suggests that they are selectively expressed in different classes of neurones and raises the possibility that some or all of them may influence neurotransmission by regulating exocytosis and/or phosphorylation.

Adenomatous polyposis coli plays a key role, in vivo, in coordinating assembly of the neuronal nicotinic postsynaptic complex

“…14-3-3 isoforms (sigma and zeta) bind to APC (Jin et al, 2004;Meek et al, 2004). 14-3-3 is present in postsynaptic densities isolated from rat brain (Martin et al, 1994;Couve et al, 2001;Rajan et al, 2002). Interaction with 14-3-3 promotes the surface expression of selected neurotransmitter receptors and ion channels (Jeanclos et al, 2001;Rajan et al, 2002;Exley et al, 2006).…”

Three-way Interaction between 14-3-3 Proteins, the N-terminal Region of Tyrosine Hydroxylase, and Negatively Charged Membranes

“…1). Using surface plasmon resonance (SPR) measurements (36), we have further characterized the membrane binding of the 14-3-3 isoforms abundant in brain and adrenal medulla (␥, , and ) (30,32,37). Furthermore, we have investigated how protein-membrane interactions were influenced by protein-protein interaction between the 14-3-3s and nonphospho-and phospho-TH N-terminal polypeptides.…”

Expression of 14-3-3 ζ and interaction with protein kinase C in the rat retina in early diabetes

“…The isotype 1 14-3-3 ζ plays a critical role in neuronal differentiation, synaptic plasticity and exocytosis [1][2][3][4][5][6]23], while PKC activation in diabetes implies diabetes-induced vascular dysfunction [14][15][16]24]. In this study, the molecular levels of 14-3-3 ζ decreased in the retina after 6 weeks of diabetes, while those of PKC β and ζ increased.…”

“…The isotype 14-3-3 ζ, along with others, has been reported to play a critical role in the central nervous system [1][2][3][4], including in neuronal differentiation [5] and synaptic plasticity [6]. Moreover, this isotype is present in significant amounts in the retina, as well as in the brain, and is necessary for light adaptation processes or differentiation in photoreceptors [7,8].…”