MAP2-mediated in vitro interactions of brain microtubules and their modulation by cAMP

• Published in: European biophysics journal Vol. 38; no. 4; pp. 381 - 393
• Main Authors: Leterrier, J. F, Kurachi, M, Tashiro, T, Janmey, P. A
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 01.04.2009; Springer-Verlag; Springer Nature B.V; Springer Verlag (Germany)
• Subjects: Adenosine Triphosphate - metabolism; Animals; Biochemistry; Biochemistry, Molecular Biology; Biological and Medical Physics; Biomedical and Life Sciences; Biophysics; Brain; Cell Biology; Cellular Biology; Cyclic AMP - metabolism; Cyclic AMP-Dependent Protein Kinases - metabolism; Elasticity; Electrophoresis, Polyacrylamide Gel; Kinases; Life Sciences; Magnesium - metabolism; Membrane Biology; Microtubule-Associated Proteins - metabolism; Microtubules - metabolism; Molecular biology; Molecular Networks; Nanotechnology; Neurobiology; Neurons; Neurons and Cognition; Original Paper; Phosphorylation; Polymers; Prosencephalon - metabolism; Protein Binding; Rats; Structural Biology; Studies; Subcellular Processes; tau Proteins - metabolism; Time; Tubulin - metabolism; Protein kinase A; Cyclic AMP; Interactions; Microtubules; Microtubule-associated protein 2; Microtubules · Microtubule-associated protein 2 · Protein kinase A · Cyclic AMP · Interactions
• ISSN: 0175-7571; 1432-1017
• DOI: 10.1007/s00249-008-0381-1

Microtubule-associated proteins (MAPs) are involved in microtubule (MT) bundling and in crossbridges between MTs and other organelles. Previous studies have assigned the MT bundling function of MAPs to their MT-binding domain and its modulation by the projection domain. In the present work, we analyse the viscoelastic properties of MT suspensions in the presence or the absence of cAMP. The experimental data reveal the occurrence of interactions between MT polymers involving MAP2 and modulated by cAMP. Two distinct mechanisms of action of cAMP are identified, which involve on one hand the phosphorylation of MT proteins by the cAMP-dependent protein kinase A (PKA) bound to the end of the N-terminal projection of MAP2, and on the other hand the binding of cAMP to the RII subunit of the PKA affecting interactions between MTs in a phosphorylation-independent manner. These findings imply a role for the complex of PKA with the projection domain of MAP2 in MT-MT interactions and suggest that cAMP may influence directly the density and bundling of MT arrays in dendrites of neurons.