Attached to nearly every human cell is an antenna-like structure known as the primary cilium, which senses the cell's environment and controls how it responds to signals from its surroundings. New research from the U.S. and Sweden has mapped and identified hundreds of proteins that comprise these structures, contributing new insights for future research into ciliary biology, disease mechanisms and potential therapies.

Publishing in the journal Cell, researchers from KTH Royal Institute of Technology and Stanford University used advanced imaging and antibody-based techniques to map proteins inside primary cilia across three types of human cells. They analyzed more than 128,000 individual cilia and identified 715 proteins that are located in different parts of the cilium responsible for sensing mechanical or chemical signals, such as hormones. These primary cilia are distinct from motile cilia, which are responsible for movement of fluids or cells.

Professor Emma Lundberg, a researcher in cellular and clinical proteomics at KTH Royal Institute of Technology, says the study also identified a possible gene behind various disorders linked to malfunctions of the cilium. These can lead to disorders affecting many parts of the body, from the brain and eyes to the kidneys and bones. In addition, the researchers discovered 91 proteins that had never before been linked to cilia.

The study expands the current understanding of cilia, casting them as highly adaptable and versatile processors of information, which tune their protein composition to suit the needs of the cell they belong to. "Cells seem to customize the protein composition of their cilia to have them perform specific sensing tasks," Lundberg says. "These newly-discovered ciliary proteins inspire many new hypotheses about their roles in cellular function and human health."

Casper Ruud captured the Stockholm Open title with a commanding 6-3, 6-2 victory over Ugo Humbert in a final that lasted just 68 minutes. The Norwegian second seed dominated throughout the match, dropping only two points on his serve in the first set and just one point in the second set. After breaking Humbert early in both sets, Ruud comfortably served out the match to claim his second title of 2025, following his earlier Masters 1000 victory in Madrid.

The victory came amid growing concerns about player welfare on the ATP Tour, highlighted by Holger Rune's season-ending injury during the tournament's semifinals. Rune had started strongly in Stockholm, reaching the semifinal round with victories over Marton Fucsovics and Tomas Martin Etcheverry before suffering a torn Achilles tendon that forced his withdrawal from the match against Humbert. The injury abruptly ended Rune's season, preventing his potential qualification for the season finale.

Ruud addressed the injury concerns in post-match comments, expressing frustration with the demanding tournament schedule. "It's very demanding when you go directly from tournament to tournament," Ruud stated. "Holger was in Shanghai last week, and when something is so demanding, something like this can unfortunately happen. We're all in some kind of risk zone when we step onto the pitch." The Norwegian added that while he couldn't confirm a direct connection between Rune's injury and the schedule, "in a way, all injuries are probably because of the tough schedule."

The concerns about player workload extend beyond Ruud's comments, with world No. 9 Jack Draper recently requesting the ATP Tour to reassess its packed calendar. Players have emphasized the need for a more manageable schedule to ensure long and healthy careers. Ruud acknowledged the physical demands, noting that players are "really pushing our own limits at the moment" and expressing sympathy for Rune's unfortunate situation while wishing him a speedy recovery.