uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
AKAP79/150 interacts with the neuronal calcium-binding protein caldendrin
Show others and affiliations
2012 (English)In: Journal of Neurochemistry, ISSN 0022-3042, E-ISSN 1471-4159, Vol. 122, no 4, 714-726 p.Article in journal (Refereed) Published
Abstract [en]

The A kinase-anchoring protein AKAP79/150 is a postsynaptic scaffold molecule and a key regulator of signaling events. At the postsynapse it coordinates phosphorylation and dephosphorylation of receptors via anchoring kinases and phosphatases near their substrates. Interactions between AKAP79 and two Ca2+ -binding proteins caldendrin and calmodulin have been investigated here. Calmodulin is a known interaction partner of AKAP79/150 that has been shown to regulate activity of the kinase PKC in a Ca2+-dependent manner. Pull-down experiments and surface plasmon resonance biosensor analyses have been used here to demonstrate that AKAP79 can also interact with caldendrin, a neuronal calcium-binding protein implicated in regulation of Ca2+ -influx and release. We demonstrate that calmodulin and caldendrin compete for a partially overlapping binding site on AKAP79 and that their binding is differentially dependent on calcium. Therefore, this competition is regulated by calcium levels. Moreover, both proteins have different binding characteristics suggesting that the two proteins might play complementary roles. The postsynaptic enrichment, the complex binding mechanism, and the competition with calmodulin, makes caldendrin an interesting novel player in the signaling toolkit of the AKAP interactome.

Place, publisher, year, edition, pages
2012. Vol. 122, no 4, 714-726 p.
Keyword [en]
calcium sensor protein, calmodulin, postsynaptic density, surface plasmon resonance
National Category
Medical and Health Sciences
URN: urn:nbn:se:uu:diva-179561DOI: 10.1111/j.1471-4159.2012.07828.xISI: 000306475700007OAI: oai:DiVA.org:uu-179561DiVA: diva2:545434
Available from: 2012-08-20 Created: 2012-08-20 Last updated: 2015-06-22Bibliographically approved
In thesis
1. Revealing Secrets of Synaptic Protein Interactions: A Biosensor based Strategy
Open this publication in new window or tab >>Revealing Secrets of Synaptic Protein Interactions: A Biosensor based Strategy
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Protein interactions are the basis of synaptic function, and studying these interactions on a molecular level is crucial for understanding basic brain function, as well as mechanisms underlying neurological disorders. In this thesis, kinetic and mechanistic characterization of synaptic protein interactions was performed by using surface plasmon resonance biosensor technology. Fragment library screening against the reverse transcriptase of HIV was included, as it served as an outlook for future drug discovery against ligand-gated ion channels.

The protein-protein interaction studies of postsynaptic Ca2+ -binding proteins revealed caldendrin as a novel binding partner of AKAP79. Caldendrin and calmodulin bind and compete at similar binding sites but their interactions display different mechanisms and kinetics. In contrast to calmodulin, caldendrin binds to AKAP79 both in the presence and absence of Ca2+ suggesting distinct in vivo functional properties of caldendrin and calmodulin.

Homo-oligomeric β3 GABAA receptors, although not yet identified in vivo, are candidates for a histamine-gated ion channel in the brain. To aid the identification of the receptor, 51 histaminergic ligands were screened and a unique pharmacology was determined. A further requirement for identifying β3 receptors in the brain, is the availability of specific high-affinity ligands. The developed biosensor assay displayed sufficient sensitivity and throughput for screening for such ligands, as well as for being employed for fragment-based drug discovery.

AMPA receptors are excitatory ligand-gated ion channels, involved in synaptic plasticity, and modulated by auxiliary proteins. Previous results have indicated that Noelin1, a secreted glycoprotein, interacts with the AMPA receptor. By using biochemical methods, it was shown that Noelin1 interacts directly with the receptor. The kinetics of the interaction were estimated by biosensor analysis, thereby confirming the interaction and suggesting low nanomolar affinity. The results provide a basis for functional characterization of a novel AMPA receptor protein interaction.

The results demonstrate how secrets of synaptic protein interactions and function were revealed by using a molecular based approach. Improving the understanding of such interactions is valuable for basic neuroscience. At the same time, the technical advancements that were achieved to study interactions of ligand-gated ion channels by surface plasmon resonance technology, provide an important tool for discovery of novel therapeutics against these important drug targets.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2014. 73 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1133
Surface plasmon resonance, biosensor, AMPA receptor, GABAA receptor, ligand-gated ion channel, A-kinase anchoring protein, caldendrin, calmodulin, HIV, fragment based drug discovery
National Category
Biochemistry and Molecular Biology Neurosciences
Research subject
Biochemistry; Neuroscience
urn:nbn:se:uu:diva-220879 (URN)978-91-554-8916-8 (ISBN)
Public defence
2014-05-16, B42, Husargatan 3, 751 23 Uppsala, 13:15 (English)
EU, FP7, Seventh Framework Programme
Available from: 2014-04-25 Created: 2014-03-22 Last updated: 2014-04-29

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Seeger, ChristianDanielson, U. Helena
By organisation
In the same journal
Journal of Neurochemistry
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 398 hits
ReferencesLink to record
Permanent link

Direct link