PMID- 22470532 OWN - NLM STAT- MEDLINE DCOM- 20120803 LR - 20211021 IS - 1932-6203 (Electronic) IS - 1932-6203 (Linking) VI - 7 IP - 3 DP - 2012 TI - Neuronal profilin isoforms are addressed by different signalling pathways. PG - e34167 LID - 10.1371/journal.pone.0034167 [doi] LID - e34167 AB - Profilins are prominent regulators of actin dynamics. While most mammalian cells express only one profilin, two isoforms, PFN1 and PFN2a are present in the CNS. To challenge the hypothesis that the expression of two profilin isoforms is linked to the complex shape of neurons and to the activity-dependent structural plasticity, we analysed how PFN1 and PFN2a respond to changes of neuronal activity. Simultaneous labelling of rodent embryonic neurons with isoform-specific monoclonal antibodies revealed both isoforms in the same synapse. Immunoelectron microscopy on brain sections demonstrated both profilins in synapses of the mature rodent cortex, hippocampus and cerebellum. Both isoforms were significantly more abundant in postsynaptic than in presynaptic structures. Immunofluorescence showed PFN2a associated with gephyrin clusters of the postsynaptic active zone in inhibitory synapses of embryonic neurons. When cultures were stimulated in order to change their activity level, active synapses that were identified by the uptake of synaptotagmin antibodies, displayed significantly higher amounts of both isoforms than non-stimulated controls. Specific inhibition of NMDA receptors by the antagonist APV in cultured rat hippocampal neurons resulted in a decrease of PFN2a but left PFN1 unaffected. Stimulation by the brain derived neurotrophic factor (BDNF), on the other hand, led to a significant increase in both synaptic PFN1 and PFN2a. Analogous results were obtained for neuronal nuclei: both isoforms were localized in the same nucleus, and their levels rose significantly in response to KCl stimulation, whereas BDNF caused here a higher increase in PFN1 than in PFN2a. Our results strongly support the notion of an isoform specific role for profilins as regulators of actin dynamics in different signalling pathways, in excitatory as well as in inhibitory synapses. Furthermore, they suggest a functional role for both profilins in neuronal nuclei. FAU - Murk, Kai AU - Murk K AD - Cellular Neurobiology, Zoological Institute, TU Braunschweig, Braunschweig, Germany. FAU - Wittenmayer, Nina AU - Wittenmayer N FAU - Michaelsen-Preusse, Kristin AU - Michaelsen-Preusse K FAU - Dresbach, Thomas AU - Dresbach T FAU - Schoenenberger, Cora-Ann AU - Schoenenberger CA FAU - Korte, Martin AU - Korte M FAU - Jockusch, Brigitte M AU - Jockusch BM FAU - Rothkegel, Martin AU - Rothkegel M LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20120328 PL - United States TA - PLoS One JT - PloS one JID - 101285081 RN - 0 (Antibodies, Monoclonal) RN - 0 (Brain-Derived Neurotrophic Factor) RN - 0 (Carrier Proteins) RN - 0 (Membrane Proteins) RN - 0 (Pfn1 protein, rat) RN - 0 (Pfn2 protein, rat) RN - 0 (Profilins) RN - 0 (Protein Isoforms) RN - 0 (gephyrin) SB - IM MH - Animals MH - Antibodies, Monoclonal/immunology MH - Brain-Derived Neurotrophic Factor/pharmacology MH - Carrier Proteins/metabolism MH - Cell Line MH - Cell Nucleus/metabolism MH - Hippocampus/metabolism MH - Membrane Proteins/metabolism MH - Mice MH - Neurons/*metabolism MH - Profilins/analysis/genetics/*metabolism MH - Protein Isoforms MH - Rats MH - *Signal Transduction MH - Synapses/drug effects/metabolism PMC - PMC3314592 COIS- Competing Interests: The authors have declared that no competing interests exist. EDAT- 2012/04/04 06:00 MHDA- 2012/08/04 06:00 PMCR- 2012/03/28 CRDT- 2012/04/04 06:00 PHST- 2011/12/16 00:00 [received] PHST- 2012/02/23 00:00 [accepted] PHST- 2012/04/04 06:00 [entrez] PHST- 2012/04/04 06:00 [pubmed] PHST- 2012/08/04 06:00 [medline] PHST- 2012/03/28 00:00 [pmc-release] AID - PONE-D-11-25234 [pii] AID - 10.1371/journal.pone.0034167 [doi] PST - ppublish SO - PLoS One. 2012;7(3):e34167. doi: 10.1371/journal.pone.0034167. Epub 2012 Mar 28.