Born in Nuremberg, Germany, Octavian O. H. Stephan studied physics and biology at FAU-University Erlangen-Nuremberg. Since 2003 he has been working in his main occupation as a research-scientist whereby he received a Dr. rer. nat. degree in Biochemistry in 2010.

His field of expertise comprises protein-biochemistry, molecular biology, and cell biology particularly regarding cellular growth processes in a variety of diverse eukaryotic organisms (yeast, fungi, plants, and animals). Moreover, in recent years he has been conducting in-depth research in the area of radiation biology for government institutions thereby analysing the effects of ionizing radiation on growth of cellular systems with a particular focus on radiation-resistance.

The research focus is centered on the elucidation of molecular signal transduction networks that regulate isotropic and anisotropic cell growth processes. Here the particular biochemical interest is on multi-subunit protein complexes and thereby on the identification of respective protein-protein, protein-DNA, and protein-membrane interactions which are involved in growth-regulation.
The interplay of cell cycle regulators (CLNs, CLBs, CDKs) with transcription factors (SWI4/SWI6/MBP1) and transcriptional regulators (RPD3, SIN3, WHI5, STB1, SAP30, RB, TOR) is analysed in the context of cell size homeostasis of yeast, plant, and human cells.
The regulatory function of plant RAC/ROP GTPases during the polar cell growth of plant cells (pollen tubes) is especially examined and the connection of RAC/ROP-effectors with the regulation of growth related processes, such as cytoskeleton dynamics or membrane trafficking is resolved.
Particularly, the influence of environmental factors on growth related processes of plant, animal, and yeast cells are analysed, whereby the focus especially lies on ionizing radiations, such as x-rays and γ-rays.


Octavian O. H. Stephan (2024). "Bio-positive effects of ionizing radiation on pollen: The role of ROS". Physiologia Plantarum, 176(1), e14163.  18 January 2024. DOI:
Octavian O. H. Stephan (2023). "Effects of environmental stress factors on the actin cytoskeleton of fungi and plants: Ionizing radiation and ROS". Cytoskeleton, 1–26, cm.21758, 17 April 2023. DOI:
Octavian O. H. Stephan, (2022). "Interactions, structural aspects, and evolutionary perspectives of the yeast ‘START’-regulatory network". FEMS Yeast Research, Volume 22, Issue 1, 2022, foab064, 14 December 2021. DOI:
Octavian O. H. Stephan (2021). "Differential interaction between RAC/ROP-GTPases and RIC-effectors: A network hub for broader signal transduction in pollen tubes". BioRxiv, 10 April 2021, bioRxiv 2021.04.09.437263. Preprint DOI:
Octavian O. H. Stephan, (2020). “Implications of ionizing radiation on pollen performance in comparison with diverse models of polar cell growth”. Plant, Cell & Environment, 44: 665–691, 30 October 2020, pce.13929.  DOI:
Octavian O. H. Stephan, (2019), “Tobacco RIC11pt differentially interacts with multiple RAC/ROP-GTPases providing a link to CAR4/GAP1”, pre-published online, 16 October 2019. 
Octavian O. H. Stephan, (2017). “Actin fringes of polar cell growth”. Journal of Experimental Botany, Volume 68, Issue 13, 3303–3320, 22 August 2017, erx195. DOI:
Octavian O. H. Stephan, Stephanie Cottier, Sara Fahlén, Adriana Montes-Rodriguez, Jia Sun, D. Magnus Eklund, Ulrich Klahre, Benedikt Kost, (2014). “RISAP Is a TGN-Associated RAC5 Effector Regulating Membrane Traffic during Polar Cell Growth in Tobacco”. The Plant Cell, 26 (11), 4426-4447, November 2014. DOI:
Octavian O. H. Stephan, Stephanie Cottier, Sara Fahlén, Ulrich Klahre, Benedikt Kost, (2012). “The N. tabacum RIPA1 gene encodes for a novel pollen tube protein involved in Rac5 GTPase dependent control of polarized cell growth”. The FEBS Journal, Volume 279, Issue s1, 70-70, September 2012.
Octavian O. H. Stephan, (2010). “The Sin3/Rpd3 histone deacetylase complex is involved in cell size control of Saccharomyces cerevisiae“. “Die Rolle des Sin3/Rpd3 Histondeacetylasekomplexes bei der Zellgrößenkontrolle in Saccharomyces cerevisiae“, urn:nbn:de:bvb:29-opus-17373, 1-147, 2010.
Octavian O. H. Stephan and Christian Koch, (2009). “Sin3 is involved in cell size control at Start in Saccharomyces cerevisiae”. The FEBS Journal 22 June 2009, 276, 3810-3824. DOI:

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