A subcellular map of the human proteome

30 organelles and substructures are annotated in the Cell Atlas.

The Cell Atlas database was just recently released with data on more than 12.000 proteins and mapping to 30 organelles. Today, the scientific findings are published in Science in "A subcellular map of the humanproteome".

The cell is a complex entity that carries out multiple functions. In order to do this, the different parts of the cells are organized in structures, called organelles. By investigating the organelles and its proteome, and to understand how the proteins vary over time and space we can truly begin to understand human biology on a detailed level.

"The Cell Atlas provides researchers with new knowledge that facilitates functional exploration of individual proteins and their role in human biology and disease." says KTH Royal Institute of Technology Professor Mathias Uhlen, director of the Human Protein Atlas. "Only by studying the molecular components of the body's smallest functional unit - the cell - can we reach a full understanding of human biology."

The Cell Atlas team has been working on the generation of the map of the subcellular human proteome for over 10 years. The project has shifted character over the years from automation and establishing robust assay platforms, to generating massive amounts of data by performing thousands of immunostainings per week, to the analysis and interpretation of the results.

Emma Lundberg, the director of the Cell Atlas, underlines that the key to successfully deliver such a complex project is: "The team!" she continues "It has been a great team effort where everyone in the team has contributed both with knowledge and know-how, and also to a great work environment."

Part of the work performed by the Cell Atlas team was highlighted in our blog last year; read about how the cells are cultured, prepared for microscopy, and the automated cell imaging.

The most intriguing findings by the team are the variation in protein expression at the single cell level and that half of all proteins localize to multiple locations. On one level, it can reflect a spatial restriction in order to control the timing of the molecular function in one compartment. On another level, such proteins may have context specific functions and "moonlight" in different parts of the cell, thus increasing the functionality of the proteome and the complexity of the cell from a systems perspective.

The Cell Atlas is the most comprehensive map of the human cell available today. It constitutes a key resource for a holistic understanding of the human cell and its complex underlying molecular machinery and is a major step towards modeling the human cell. With its plethora of images it is also a highly valuable resource for machine learning applications in image pattern recognition.

The Cell Atlas is an open access knowledge resource that can be freely used by researchers around the world to study proteins or organelles of interest allowing systems biology and cell modeling applications.

Emma concludes: "We will continue to work towards a fully validated Cell Atlas with complete coverage of the human proteome. Our vision is to generate a model of the spatial distribution of the human proteome in a canonical human call over the course of a cell cycle."

Read more about the results in the Science article: A subcellular map of the humanproteome.

Tove Alm