Simulations show kinesin's neck region steers steps counterclockwise
New CapabilitiesAtomic-scale models run on Japan's Fugaku supercomputer resolve the long-unseen structure of the motor's guiding neck
Today: Top story on r/scienceNew here? Follow stories to track developments over time. Create a free account to get updates when stories you care about change.
Overview
Updated 1 hour agoKinesin is the two-footed motor that hauls cargo through cells by walking along filaments called microtubules. The 'neck' segment that coordinates each step has resisted direct imaging for decades, so researchers simulated it atom-by-atom on Japan's Fugaku supercomputer — the system that was the world's fastest from 2020 to 2022.
The model shows the neck lying perpendicular to the microtubule, pressed against its surface. That contact steers the rear foot in a counterclockwise arc around the front foot, directing each step forward. The result is a structural mechanism for stepping bias that has been missing since kinesin was discovered in 1985.
Why it matters
Every cell depends on kinesin to move cargo; this study resolves how its neck guides those steps, a structural question open since the motor's discovery.
Questions about this story
Free account needed to ask — your question is kept and asked for you right after sign-up. Answers are public.
No questions yet — be the first to ask.
Key Indicators
Voices
Curated perspectives — historical figures and your fellow readers.
Play
Exploring all sides of a story is often best achieved with Play.
Higher or Lower
A number from this story, against one from elsewhere in the news — guess which is bigger, then keep the chain going. 5 rounds, 3 strikes; a miss costs a strike and resets your streak.
Keyboard: ↓/L lower · ↑/H higher
0 points — sign up to put that on the leaderboard.
Connections
Sixteen names from the news. Find the four hidden groups of four. Four mistakes max.
Sign up to keep a daily streak — a new puzzle lands every day.
Exit debate?
Your progress in this debate will be lost.
- 1 Two AI personas square off on this story.
- 2 You predict who'll win each round — correct picks earn XP.
- 3 One crossfire question is yours to fire. Pick it carefully.
Couldn't generate a topic
Select Your Champions
Choose one persona for each side of the debate
DEBATE TOPIC
Choose personas with different perspectives for a more dynamic debate.
Select debater for this side:
No debate personas available right now.
Select debater for this side:
No debate personas available right now.
Who's Got This Round?
Make your prediction before the referee scores
The referee scores both sides on
Round Results
Set the Crossfire
Pick the question both personas must answer in the final round
Debate Oracle! You called every round!
Sharp Instincts! You know your debaters!
The Coin Flip Strategist! Perfectly balanced!
The Contrarian! Bold predictions!
Inverse Genius! Try betting the opposite next time!
XP Breakdown
Prediction History
People Involved
Organizations Involved
Inter-university research institute in Okazaki, Japan, specializing in molecular science.
National university in Kumamoto, Japan, active in computational biophysics research.
The world's fastest supercomputer from June 2020 to May 2022, used here to run 3-million-atom simulations.
Timeline
June 2025 September 2026
-
Top story on r/science
Today PublicityThe finding becomes the top post on Reddit's r/science community.
-
Study appears in Biophysical Journal
PublicationIMS announces the study's publication in Biophysical Journal, with coverage on Phys.org and Life Technology the same day.
-
Preprint posted to bioRxiv
PreprintResearchers post their kinesin neck simulations study to bioRxiv before peer review.
Historical Context
3 moments from history that rhyme with this story — and how they unfolded.
Discovery of kinesin (1985)
Ronald Vale and colleagues identified kinesin in squid giant axons using video-enhanced differential interference contrast microscopy. It was the first motor protein found to walk along microtubules.
The discovery opened a new research field focused on how cells transport cargo along filaments.
Kinesin research has since spanned four decades, producing a detailed picture of the motor's chemistry but leaving its neck region's structure unresolved.
This study closes exactly the structural gap left open since kinesin was named in 1985.
Hand-over-hand debate resolved (2004)
Yildiz and colleagues used single-molecule fluorescence to show kinesin's two heads alternate — the rear head passes the front head with each step. This settled a hand-over-hand versus inchworm debate.
The field accepted that kinesin walks by alternating head positions, each head taking 16-nanometer steps.
The alternation mechanism became textbook knowledge, but the question of what steers the passing motion remained open.
The current paper addresses precisely what that 2004 work left unresolved: how the neck region biases the direction of the passing step.
Myosin V lever-arm mechanism (early 2000s)
Single-molecule and structural studies of myosin V — another two-footed processive motor — revealed how a long alpha-helical neck converts ATP hydrolysis into large directional steps along actin filaments.
Researchers gained a template for how processive motors translate chemical energy into directed motion.
The lever-arm model became the reference point for motor protein mechanisms, prompting questions about whether kinesin uses a similar strategy.
Kinesin's neck plays an analogous role to myosin's lever arm, and this study now specifies how kinesin's version produces directional bias.
