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Event: 1884

Key Event Title

The KE title should describe a discrete biological change that can be measured. It should generally define the biological object or process being measured and whether it is increased, decreased, or otherwise definably altered relative to a control state. For example “enzyme activity, decreased”, “hormone concentration, increased”, or “growth rate, decreased”, where the specific enzyme or hormone being measured is defined. More help

Inhibition of Fyna

Short name
The KE short name should be a reasonable abbreviation of the KE title and is used in labelling this object throughout the AOP-Wiki. The short name should be less than 80 characters in length. More help
Inhibition of Fyna

Biological Context

Structured terms, selected from a drop-down menu, are used to identify the level of biological organization for each KE. Note, KEs should be defined within a particular level of biological organization. Only KERs should be used to transition from one level of organization to another. Selection of the level of biological organization defines which structured terms will be available to select when defining the Event Components (below). More help

Cell term

Further information on Event Components and Biological Context may be viewed on the attached pdf.The biological context describes the location/biological environment in which the event takes place.  For molecular/cellular events this would include the cellular context (if known), organ context, and species/life stage/sex for which the event is relevant. For tissue/organ events cellular context is not applicable.  For individual/population events, the organ context is not applicable. More help

Organ term

Further information on Event Components and Biological Context may be viewed on the attached pdf.The biological context describes the location/biological environment in which the event takes place.  For molecular/cellular events this would include the cellular context (if known), organ context, and species/life stage/sex for which the event is relevant. For tissue/organ events cellular context is not applicable.  For individual/population events, the organ context is not applicable. More help

Key Event Components

Further information on Event Components and Biological Context may be viewed on the attached pdf.Because one of the aims of the AOP-KB is to facilitate de facto construction of AOP networks through the use of shared KE and KER elements, authors are also asked to define their KEs using a set of structured ontology terms (Event Components). In the absence of structured terms, the same KE can readily be defined using a number of synonymous titles (read by a computer as character strings). In order to make these synonymous KEs more machine-readable, KEs should also be defined by one or more “event components” consisting of a biological process, object, and action with each term originating from one of 22 biological ontologies (Ives, et al., 2017; See List). Biological process describes dynamics of the underlying biological system (e.g., receptor signalling). The biological object is the subject of the perturbation (e.g., a specific biological receptor that is activated or inhibited). Action represents the direction of perturbation of this system (generally increased or decreased; e.g., ‘decreased’ in the case of a receptor that is inhibited to indicate a decrease in the signalling by that receptor).Note that when editing Event Components, clicking an existing Event Component from the Suggestions menu will autopopulate these fields, along with their source ID and description. To clear any fields before submitting the event component, use the 'Clear process,' 'Clear object,' or 'Clear action' buttons. If a desired term does not exist, a new term request may be made via Term Requests. Event components may not be edited; to edit an event component, remove the existing event component and create a new one using the terms that you wish to add. More help
Process Object Action
protein tyrosine kinase activity tyrosine-protein kinase fyna (zebrafish) decreased

Key Event Overview

AOPs Including This Key Event

All of the AOPs that are linked to this KE will automatically be listed in this subsection. This table can be particularly useful for derivation of AOP networks including the KE. Clicking on the name of the AOP will bring you to the individual page for that AOP. More help
AOP Name Role of event in AOP Point of Contact Author Status OECD Status
Inhibition of Fyna leading to increased mortality MolecularInitiatingEvent Vid Modic (send email) Under development: Not open for comment. Do not cite


This is a structured field used to identify specific agents (generally chemicals) that can trigger the KE. Stressors identified in this field will be linked to the KE in a machine-readable manner, such that, for example, a stressor search would identify this as an event the stressor can trigger. NOTE: intermediate or downstream KEs in one AOP may function as MIEs in other AOPs, meaning that stressor information may be added to the KE description, even if it is a downstream KE in the pathway currently under development.Information concerning the stressors that may trigger an MIE can be defined using a combination of structured and unstructured (free-text) fields. For example, structured fields may be used to indicate specific chemicals for which there is evidence of an interaction relevant to this MIE. By linking the KE description to a structured chemical name, it will be increasingly possible to link the MIE to other sources of chemical data and information, enhancing searchability and inter-operability among different data-sources and knowledgebases. The free-text section “Evidence for perturbation of this MIE by stressor” can be used both to identify the supporting evidence for specific stressors triggering the MIE as well as to define broad chemical categories or other properties that classify the stressors able to trigger the MIE for which specific structured terms may not exist. More help

Taxonomic Applicability

Latin or common names of a species or broader taxonomic grouping (e.g., class, order, family) can be selected from an ontology. In many cases, individual species identified in these structured fields will be those for which the strongest evidence used in constructing the AOP was available in relation to this KE. More help
Term Scientific Term Evidence Link
zebrafish Danio rerio High NCBI

Life Stages

The structured ontology terms for life-stage are more comprehensive than those for taxa, but may still require further description/development and explanation in the free text section. More help
Life stage Evidence
Larvae High

Sex Applicability

The authors must select from one of the following: Male, female, mixed, asexual, third gender, hermaphrodite, or unspecific. More help
Term Evidence
Unspecific High

Key Event Description

A description of the biological state being observed or measured, the biological compartment in which it is measured, and its general role in the biology should be provided. For example, the biological state being measured could be the activity of an enzyme, the expression of a gene or abundance of an mRNA transcript, the concentration of a hormone or protein, neuronal activity, heart rate, etc. The biological compartment may be a particular cell type, tissue, organ, fluid (e.g., plasma, cerebrospinal fluid), etc. The role in the biology could describe the reaction that an enzyme catalyses and the role of that reaction within a given metabolic pathway; the protein that a gene or mRNA transcript codes for and the function of that protein; the function of a hormone in a given target tissue, physiological function of an organ, etc. Careful attention should be taken to avoid reference to other KEs, KERs or AOPs. Only describe this KE as a single isolated measurable event/state. This will ensure that the KE is modular and can be used by other AOPs, thereby facilitating construction of AOP networks. More help

Src family kinases (SFKs) include nine members (i.e., Src, Fyn, Yes, Blk, Yrk, Fgr, Hck, Lck and Lyn) and regulate multiple signal transduction pathways involved in growth, proliferation, differentiation, migration, metabolism and apoptosis, interacting with a diverse array of molecules, including growth factor receptors, cell–cell adhesion receptors, integrins and steroid hormone receptors (Schenone et al., 2007). Protein kinases enable transfer of γ phosphate of ATP to specific amino acids of protein substrates (tyrosine, serine, threonine, or even histidine residues) (Saito, 2001). Phosphorylation of certain tyrosine residues changes the enzymatic activity of tyrosine kinases and regulates specificity for substrate binding, localization, and recruitment of downstream signaling proteins. There are two major groups of tyrosine kinases: receptor and nonreceptor tyrosine kinases. Nonreceptor tyrosine kinases (cytoplasmatic proteins) are important components of signaling pathways through different receptors such as receptor tyrosine kinases, G-protein coupled receptors, or T-cell receptors (TCR) on the cell surface (Hanrs & Hunter2, n.d.).

Fyna (Src family tyrosine kinase A) is a nonreceptor tyrosine kinase.  It is involved in several processes, including adherens junction maintenance; gastrulation; and protein autophosphorylation. Localizes to cytosol and nucleus. Is expressed in central nervous system; olfactory placode; peripheral olfactory organ; and retina. Human ortholog(s) of this gene are implicated in Alzheimer's disease and schizophrenia. Fyna is orthologous to human FYN (FYN proto-oncogene, Src family tyrosine kinase) (ZFIN Gene: Fyna, n.d.). Zebrafish Fyna gene shares 89% sequence identity (full length sequence and kinase domain) with human Fyn gene (Challa & Chatti, 2013).

The Src family kinases are of a modular nature, consisting of a unique N-terminal sequence, three protein modules including the SH3, SH2, and kinase domains, and a C-terminal tail. The modules play an important role in enzyme reactions (Lamers et al., 2003). Fyna kinase activity, like that of other Src family kinases, is regulated by intramolecular interactions that depend on equilibrium between tyrosine phosphorylation and dephosphorylation. In the basal state, catalytic activity is constrained by engagement of the SH2 domain by a phosphorylated C-terminal tyrosine 531(Krämer-Albers & White, 2011). Crystal structures of the SH2 and SH3 domains of the Fyna kinase reveal its binding specificity for peptide inhibitors (Morton et al., 1996; Mulhern et al., 1997). Binding of inhibitors to fyna domains inhibits its activity. Research in inhibition of Fyna kinase is mostly due its role in Alzheimer's disease (AD) and anti-inflamatory therapy (Löwenberg et al., 2005).

There are multiple known Fyna kinase inhibitors (see Evidence for perturbation by stressor).

How It Is Measured or Detected

One of the primary considerations in evaluating AOPs is the relevance and reliability of the methods with which the KEs can be measured. The aim of this section of the KE description is not to provide detailed protocols, but rather to capture, in a sentence or two, per method, the type(s) of measurements that can be employed to evaluate the KE and the relative level of scientific confidence in those measurements. Methods that can be used to detect or measure the biological state represented in the KE should be briefly described and/or cited. These can range from citation of specific validated test guidelines, citation of specific methods published in the peer reviewed literature, or outlines of a general protocol or approach (e.g., a protein may be measured by ELISA).Key considerations regarding scientific confidence in the measurement approach include whether the assay is fit for purpose, whether it provides a direct or indirect measure of the biological state in question, whether it is repeatable and reproducible, and the extent to which it is accepted in the scientific and/or regulatory community. Information can be obtained from the OECD Test Guidelines website and the EURL ECVAM Database Service on Alternative Methods to Animal Experimentation (DB-ALM). ?

Changes in activity of Fyna kinase can be evaluated with ELISA kinase assay. Inhibition of Fyna enzyme activity with rosmarinic acid and staurosporine has been investigated using enzyme-linked immunosorbent assay (ELISA). This type of ELISA method is based on kinase phosphorylation of immobilized substrate, which is detected using anti-tyrosine phosphate antibody. The extent of the substrate phosphorylation can be measured by absorbance, fluorescence, or fluorescence polarization (Jelić et al., 2007).

Adp-GloTM Kinase Assay can be used to measure Fyna kinase activity. The assay is well suited for measuring the effects chemical compounds have on the activity of a broad range of purified kinases, making it ideal for both primary screening as well as kinase selectivity profiling (Ma et al., n.d.).

Domain of Applicability

This free text section should be used to elaborate on the scientific basis for the indicated domains of applicability and the WoE calls (if provided). While structured terms may be selected to define the taxonomic, life stage and sex applicability (see structured applicability terms, above) of the KE, the structured terms may not adequately reflect or capture the overall biological applicability domain (particularly with regard to taxa). Likewise, the structured terms do not provide an explanation or rationale for the selection. The free-text section on evidence for taxonomic, life stage, and sex applicability can be used to elaborate on why the specific structured terms were selected, and provide supporting references and background information.  More help

Theoretically, this MIE is applicable to any organisms that possess Fyna kinase (zebrafish and other vertebrate models). In zebrafish Fyna inhibition was achieved with kinase dead (KD) point mutant of Fyna (St. Clair et al., 2018).

Evidence for Perturbation by Stressor

Overview for Molecular Initiating Event

When a specific MIE can be defined (i.e., the molecular target and nature of interaction is known), in addition to describing the biological state associated with the MIE, how it can be measured, and its taxonomic, life stage, and sex applicability, it is useful to list stressors known to trigger the MIE and provide evidence supporting that initiation. This will often be a list of prototypical compounds demonstrated to interact with the target molecule in the manner detailed in the MIE description to initiate a given pathway (e.g., 2,3,7,8-TCDD as a prototypical AhR agonist; 17α-ethynyl estradiol as a prototypical ER agonist). Depending on the information available, this could also refer to chemical categories (i.e., groups of chemicals with defined structural features known to trigger the MIE). Known stressors should be included in the MIE description, but it is not expected to include a comprehensive list. Rather initially, stressors identified will be exemplary and the stressor list will be expanded over time. For more information on MIE, please see pages 32-33 in the User Handbook.

Rosmarinic acid

Rosmarinic acid, a secondary metabolite of herbal plants, was discovered as a new Fyna kinase inhibitor using immunochemical and in silico methods. Kinetic data implicate that rosmarinic acid inhibits Fyna kinase in a linear-mixed type of inhibition. In this type of reversible inhibition, a compound can interact both with the free enzyme and with the enzyme-substrate complex at a site other than the active site (Jelić et al., 2007).

CAS: 20283-92-5


Dual SFK inhibitors (e.g., dasatinib, bosutinib and saracatinib) already approved for therapy or are in clinical trials (Musumeci et al., 2012). Saracatinib (AZD0530) is a small molecule inhibitor of Src family kinases, inhibiting Src, Fyna, Yes and Lyn, with 2 to 10 nM potency. AZD0530 specific inhibition of Fyna and other SFKs has led to its development as therapy for solid tumors, because Src family kinases regulate tumor cell adhesion, migration and invasion, and also regulate proliferation (Hennequin et al., 2006). AZD0530 has numerous desirable properties. For example, AZD0530 inhibits Fyna activity in the low nM range (Green et al., 2009) has a half‐life of 16 hours in the mouse and is highly brain penetrable (Kaufman et al., 2015).


Staurosporine is a microbial alkaloid isolated from Streptomyces sp. (Omura, S.,1977) which has been shown to be a potent broad-range inhibitor competing with ATP, but not peptide substrate, for binding to protein kinases including Fyn kinase. Staurosporine binds to the ATP-binding site of Fyn (Kinoshita et al., 2006) and has nanomolar potency against most protein kinases including Fyn. This level of selectivity has already enabled staurosporine to be used as a lead inhibitor for the design of specific potent protein kinase inhibitors (Toullec et al., 1991).


List of the literature that was cited for this KE description. Ideally, the list of references, should conform, to the extent possible, with the OECD Style Guide ( (OECD, 2015). More help

Challa, A. K., & Chatti, K. (2013). Conservation and Early Expression of Zebrafish Tyrosine Kinases Support the Utility of Zebrafish as a Model for Tyrosine Kinase Biology. 10(3).

Green, T. P., Fennell, M., Whittaker, R., Curwen, J., Jacobs, V., Allen, J., Logie, A., Hargreaves, J., Hickinson, D. M., Wilkinson, R. W., Elvin, P., Boyer, B., Carragher, N., Plé, P. A., Bermingham, A., Holdgate, G. A., Ward, W. H. J., Hennequin, L. F., Davies, B. R., & Costello, G. F. (2009). Preclinical anticancer activity of the potent, oral Src inhibitor AZD0530. Molecular Oncology, 3(3), 248–261.

Hanrs, S. K., & Hunter2, T. (n.d.). The eukaryotic protein kinase superfamily: idnase. (catalytic) domam structure and classification.

Jelić, D., Mildner, B., Koštrun, S., Nujić, K., Verbanac, D., Čulić, O., Antolović, R., & Brandt, W. (2007). Homology modeling of human Fyn kinase structure: Discovery of rosmarinic acid as a new Fyn kinase inhibitor and in Silico study of its possible binding modes. Journal of Medicinal Chemistry, 50(6), 1090–1100.

Kinoshita, T., Matsubara, M., Ishiguro, H., Okita, K., & Tada, T. (2006). Structure of human Fyn kinase domain complexed with staurosporine. Biochemical and Biophysical Research Communications, 346(3), 840–844.

Krämer-Albers, E.-M., & White, R. (2011). From axon-glial signalling to myelination: the integrating role of oligodendroglial Fyn kinase. Cell. Mol. Life Sci.

Lamers, M. B. A. C., Antson, A. A., Hubbard, R. E., Scott, R. K., & Williams, D. H. (2003). Structure of the Protein Tyrosine Kinase Domain of C-terminal Src Kinase (CSK) in Complexwith Staurosporine. J. Mol. Bi(285), 713–725. papers2://publication/uuid/CBF6FE3B-FE88-4A68-9E4A-EC387CF85D43

Löwenberg, M., Tuynman, J., Bilderbeek, J., Gaber, T., Buttgereit, F., Van Deventer, S., Peppelenbosch, M., & Hommes, D. (2005). Rapid immunosuppressive effects of glucocorticoids mediated through Lck and Fyn. Blood, 106(5), 1703–1710.

Ma, B. D., Zegzouti, H., Ph, D., Vidugiriene, J., Ph, D., Goueli, S. A., Ph, D., & Corporation, P. (n.d.). FYN A Kinase Assay.

Morisot, N., Berger, A. L., Phamluong, K., Cross, A., & Ron, D. (2019). The Fyn kinase inhibitor, AZD0530, suppresses mouse alcohol self-administration and seeking. Addiction Biology, 24(6), 1227–1234.

Nygaard, H. B., Van Dyck, C. H., & Strittmatter, S. M. (2014a). Fyn kinase inhibition as a novel therapy for Alzheimer’s disease.

Nygaard, H. B., Van Dyck, C. H., & Strittmatter, S. M. (2014b). Fyn kinase inhibition as a novel therapy for Alzheimer’s disease. Alzheimer’s Research and Therapy, 6(1), 1–8.

Saito, H. (2001). Histidine phosphorylation and two-component signaling in eukaryotic cells. Chemical Reviews, 101(8), 2497–2509.

St. Clair, R. M., Emerson, S. E., D’Elia, K. P., Weir, M. E., Schmoker, A. M., Ebert, A. M., & Ballif, B. A. (2018). Fyn-dependent phosphorylation of PlexinA1 and PlexinA2 at conserved tyrosines is essential for zebrafish eye development. FEBS Journal, 285(1), 72–86.

Toullec, D., Pianetti, P., Coste, H., Bellevergue, P., Grand-Perret, T., Ajakane, M., Baudet, V., Boissin, P., Boursier, E., Loriolle, F., Duhamel, L., Charon, D., & Kirilovsky, J. (1991). The bisindolylmaleimide GF 109203X is a potent and selective inhibitor of protein kinase C. Journal of Biological Chemistry, 266(24), 15771–15781.

         ZFIN Gene: fyna. (n.d.). Retrieved March 14, 2021, from