P7: Identification of cGMP-dependent protein kinase I substrates mediating sensory axon bifurcation


Further dissection of the CNP-induced cGMP signaling cascade that regulates sensory axon bifurcation for a better mechanistic understanding of axonal growth, guidance and branching.

cGMP and Axon Branching

Questions and Methods

Boston Internship

Blanton Lab

In the Blanton lab in Boston, the doctoral researchers will receive training in several biochemical screening methods for cGKI substrates, including GST-pulldown studies using a cGKI-LZM mutant protein, direct cGMP pulldowns, and standard immunoprecipitations.

These techniques will also be instrumental for the validation of putative novel interaction partners of cGKI resulting from analyses using the analog-sensitive kinase mutant and the SILAC approach (see above).

Boston Co-mentor

Assist. Prof. Robert M. Blanton, MD

Link to boston researcher lab

Doctoral Students

Alexandra Böttcher

Alexandra Böttcher started her studies in the field of biochemistry at Ulm University, conducting her Bachelor's thesis on electrophysiological analysis of the dopamine response of substantia nigra neurons. Taking the opportunity to follow her interest in neurophysiological research, she continued at Ulm University and earned her Master's degree in Molecular and Translational Neuroscience. Her thesis focused on the influence of the gut microbiome on chronic psychosocial stress. Aiming to utilize innovative biochemical methodology in neuroscientific research, Alexandra joined the group of Hannes Schmidt as a doctoral student. Her main research interest lies in the role of cGMP signaling in sensory axon branching during embryonal spinal cord development.

Shahzad Munir

Shahzad Munir completed his bachelor in biological sciences from the Heidelberg University where he demonstrated a potential interaction between ERM protein family and membrane-bound activated leukocyte cell adhesion molecule (ALCAM) which plays a crucial role in axonal guidance and pathfinding during development. Continuing his master studies at Heidelberg University, he characterized a novel zeolite-based monoaminergic sensor, which culminated into his master thesis. His interest in fundamental neuroscience research led him to join the group of Dr. Hannes Schmidt to investigate the CNP-induced cGMP signalling in the hippocampus.

Michael Krämer (associated PhD student)

Michael Krämer earned his B.Sc. in biochemistry at the University of Tübingen with a focus on proteomics and protein biochemistry. After his bachelors, he went to continue with his studies in protein biochemistry and earned his M.Sc. in biochemistry also in Tübingen. Michael's keen interest in protein interactions and cellular signaling prompted him to start a PhD at the laboratory of PD Dr. Hannes Schmidt. Among other things, his main research interest focuses on CNP/GC-B mediated cGMP signaling in the gastrointestinal tract.

Key Publications

Schmidt H, Stonkute A, Jüttner R, Koesling D, Friebe A, Rathjen FG. C-type natriuretic peptide (CNP) is a bifurcation factor for sensory neurons. Proc Natl Acad Sci U S A. 2009;106:16847-52

Ter-Avetisyan G, Rathjen FG, Schmidt H.  Bifurcation of axons from cranial sensory neurons is disabled in the absence of Npr2-induced cGMP signaling. J Neurosci. 2014;34:737-47

Schmidt H, Fritzsch B. Npr2 null mutants show initial overshooting followed by reduction of spiral ganglion axon projections combined with near-normal cochleotopic projection. Cell Tissue Res 2019;378(1):15-32.

Zalucki O, Harris L, Harvey TJ, Harkins D, Widagdo J, Oishi S, Matuzelski E, Yong XLH, Schmidt H, Anggono V, Burne THJ, Gronostajski RM, Piper M. NFIX-mediated inhibition of neuroblast branching regulates migration within the adult mouse ventricular-subventricular zone. Cereb Cortex 2019;29(8):3590–604

Lauffer P, Miranda-Laferte E, van Duyvenvoorde HA, van Haeringen A, Werner F, Boudin E, Schmidt H, Mueller TD, Kuhn M, van der Kaay DCM. An activating deletion variant in the sub-membrane region of natriuretic peptide receptor-B causes tall stature. J Clin Endocrinol Metab 2020;105(7):2354–66

Zink J, Frye M, Frömel T, Carlantoni C, John D, Schreier D, Weigert A, Laban H, Salinas G, Stingl H, Günther L, Popp R, Hu J, Vanhollebeke B, Schmidt H, Acker-Palmer A, Renné T, Fleming I & Benz PM. EVL regulates VEGF receptor-2 internalization and signaling in developmental angiogenesis. EMBO reports 2021;22: e48961.

Dumoulin A, Schmidt H, Rathjen FG. Sensory Neurons: The formation of T-shaped branches is dependent on a cGMP-dependent signaling cascade. Neuroscientist 2021;27(1): 47-57.

Krämer MS, Feil R, Schmidt H. Analysis of gene expression using lacZ reporter mouse lines. in ‛Mouse Genetics – Methods and Protocols’ Meth Mol Biol (Springer Protocols) 2021;2224:29-45. Editors Singh SR, Hoffman RM, and Singh A.