A team of scientists from the University of Chile has identified and characterized for the first time the complete set of protein kinases in Atlantic salmon (Salmo salar), revealing the most extensive “kinome” ever reported in the animal kingdom. This genetic map not only unveils the secrets of the fish’s muscle development but also opens new avenues for optimizing growth and sustainability in aquaculture.
Enhancing salmon growth, particularly the development of its muscle mass, is a constant objective for the sector. To achieve this, it is crucial to understand the molecular mechanisms that regulate these processes at the cellular level.
At the heart of this regulation lies phosphorylation, a vital biochemical process directed by a superfamily of enzymes called protein kinases (PKs). These act as molecular switches, activating or deactivating other proteins to control virtually all cellular processes, from growth to immune response.
A recent study published in the journal Aquaculture has mapped for the first time the complete set of these enzymes in Atlantic salmon, known as the kinome, providing an unprecedented basis for future research and biotechnological applications.
A record-breaking Kinome: The largest in the animal kingdom
Using a comprehensive bioinformatic approach, researchers identified a total of 1,294 kinase genes in the salmon genome. This finding positions the Atlantic salmon as the animal species with the largest kinome reported to date.
The kinome is divided into two main categories:
- 1,157 eukaryotic protein kinases (ePKs): Conventional kinases, classified into nine groups. The most abundant groups were the Tyrosine Kinases (TK) and the Calcium/calmodulin-dependent Protein Kinases (CAMK).
- 137 atypical protein kinases (aPKs): A more diverse group that lacks the typical structure of ePKs but performs crucial functions.
Why such a high number?
The authors suggest that the main reason lies in the salmon’s evolutionary history, which includes two whole-genome duplication (WGD) events—one shared by teleost fish and another exclusive to salmonids. These events multiplied the genetic material, allowing some gene copies to evolve and acquire new functions.
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Additionally, the study identified 96 pseudokinases—versions of these enzymes that, due to mutations in key sites, are predicted to be catalytically inactive but may play important regulatory roles in signaling pathways.
“While the complete mapping of the salmon kinome (the set of all its kinases) is a fundamental milestone in itself, the most significant findings are twofold. First, we discovered that salmon possess the largest kinome reported in the animal kingdom, even larger than the human kinome. Second, and despite this size difference, we found that these enzymes are highly conserved evolutionarily between both species, which opens up the possibility of using what is known in humans to apply it to salmon, and in turn, using salmon as a biomedical study model,” explained Dr. Rodrigo Pulgar, a member of the Institute of Nutrition and Food Technology at the University of Chile.
Focus on muscle: The Kinases driving growth
Muscle is the most economically important tissue in salmon. To understand the specific role of the kinome in this tissue, scientists analyzed the expression of kinase genes in six different organs: muscle, liver, brain, gills, intestine, and anterior kidney.
The results showed highly specific expression patterns for each tissue, suggesting that each organ uses a “toolkit” of kinases adapted to its needs. In the muscle, the differential analysis revealed:
- 99 kinases that were significantly more abundant than in other tissues.
- 53 kinases with lower abundance.
Upon analyzing the functions of the most abundant kinases in muscle, researchers found they are enriched in biological processes vital for muscle development and function, such as:
- Striated muscle differentiation and development.
- Calcium signaling and calmodulin binding.
- Regulation of the MAPK signaling pathway, key for cell proliferation and differentiation.
- Muscle contraction and cytoskeleton organization.
Among the most prominent kinases were two paralogous genes of TITIN, one of the most abundant proteins in muscle, whose kinase domain is essential for contraction.
Salmon vs. human: A conserved genetic relationship
To contextualize their findings, the team compared the salmon kinome with the human kinome, which is one of the most well-studied. Despite the salmon having more than double the number of kinase genes, the study revealed a high degree of conservation between the two species.
The average identity in the catalytic domains of kinases between salmon and humans was nearly 81%, reaching over 89% in groups like CK1. This similarity underscores the fundamental importance of these enzymes in vertebrates and suggests that their basic functions have been maintained throughout evolution.
Interestingly, notable differences were also found. Kinase families such as WNK and IRE, which are more represented in salmon, are involved in osmoregulation and stress response—critical functions for a fish that transitions between freshwater and saltwater.
“The next step is functional validation: determining the specific role of particular kinases in phenotypes of interest. The great advantage we have is the evolutionary conservation with humans. This allows us to use kinase-inhibiting drugs already approved in human medicine to test their effects on salmon systems,” highlighted Pulgar.
Conclusions and implications for aquaculture
This study represents a milestone in Atlantic salmon genomics. By providing the first complete and annotated catalog of the kinome, it establishes a solid foundation for future functional research.
The implications for aquaculture are significant. Understanding which specific kinases control muscle growth could enable the development of:
- Genetic selection strategies to breed fish with greater growth potential.
- Functional diets that modulate the activity of these signaling pathways to improve muscle protein deposition.
- New approaches to study salmon health and physiology in response to different farming conditions.
The high degree of conservation with the human kinome also offers a practical advantage: the possibility of using kinase inhibitors already developed for human medicine as research tools to validate the function of specific kinases in salmon.
In summary, this detailed genetic map of protein kinases opens a new window for understanding salmon biology and provides valuable molecular tools to address the challenges of more efficient and sustainable aquaculture production.
The study was funded by ANID Fondecyt Regular #1221848, ANID Exploration Project #13240202, and ANID Chilean Doctoral Scholarship #21222070.
Reference:
Vera-Tamargo, F., Galdames-Contreras, F., Hödar, C., & Pulgar, R. (2026). Genome-wide prediction and gene expression profiling of the Atlantic Salmon Kinome. Aquaculture, 611, 743033. https://doi.org/10.1016/j.aquaculture.2025.743033
Editor at the digital magazine AquaHoy. He holds a degree in Aquaculture Biology from the National University of Santa (UNS) and a Master’s degree in Science and Innovation Management from the Polytechnic University of Valencia, with postgraduate diplomas in Business Innovation and Innovation Management. He possesses extensive experience in the aquaculture and fisheries sector, having led the Fisheries Innovation Unit of the National Program for Innovation in Fisheries and Aquaculture (PNIPA). He has served as a senior consultant in technology watch, an innovation project formulator and advisor, and a lecturer at UNS. He is a member of the Peruvian College of Biologists and was recognized by the World Aquaculture Society (WAS) in 2016 for his contribution to aquaculture.
