EDMONTON - University of Alberta researchers are rewriting the textbooks with a discovery that alters science's understanding of one of the cell's most basic processes.
The finding could shed new light on the origin of some of the most mysterious and threatening neurological diseases, including Alzheimer's and Huntington's disease.
"This opens up a whole new avenue of research in the biology of the cell" said Joel Dacks, an evolutionary cell biologist who co-authored the paper published Tuesday in which the discovery is described.
Dacks' lab, together with colleagues at England's Cambridge University, discovered an entirely new pathway through which material can move within a cell.
Until now, science believed there were four protein complexes, called adaptins, that move molecules within the cell, absorb them or shove them outside the cell wall.
"Protein gets made in one place, shuttled to another location and then it gets packaged for delivery elsewhere in the cell," Dacks said. "The adaptin complexes are involved in the later stages of sending things out to the various locations.
"Scientists had been using these four protein complexes to explain those pathways. We found a fifth one."
That fifth pathway is present in a wide variety of cells, from human cells to plants cells to one-celled amoebas, suggesting it evolved a long time ago. That means it may hold important clues as to how cells evolved over the eons from simple structures Dacks compares to a bachelor's apartment to modern cells that are more like three-bedroom condos.
"They are telling us something important about the order in which these things evolved," he said.
But the fifth adaptin may also hold secrets about some of humanity's most baffling — and tragic — diseases.
Dacks said these adaptin pathways within the cell are often involved in transporting hormones and other chemicals that allow cells to communicate with each other. When those pathways break down, neurodegenerative disease is often the result.
"We know they are associated with certain diseases," he said. "Alzheimer's is an adaptin four-associated disease."
The new, fifth adaptin, is already linked to hereditary spastic paraplegia, a rare disease that causes leg spasms and eventually robs the sufferer of mobility. And just knowing there's a fifth adaptin in the mix will change how scientists look at the previously known four.
As well, parasites can use the adaptin pathways to evade the body's immune system and invade cells.
"Understanding what these genes might be doing in parasites is a really exciting possibility. There are a number of important diseases that this might able to help us in understanding," Dacks said.
But for now, Dacks will bask in the glow of a discovery that sheds new light on some of life's most basic processes. The fifth adaptin, he said, will force a small but significant shift in the scientific understanding of life's basic building block — the cell.
"Maybe people need to go back and ask, 'So, how do we talk about moving material around if we have five players, not four?'
"This is just the beginning of decades more work."