A group of academics who may have finally lost it
The Proteolipid Code
Arguably the largest cellular code in terms of mass, volume, and number of components. We said arguably. Please don't email us.
Chapter I
What Is the Proteolipid Code?
The proteolipid code lives in a topological space and is responsible for the subcellular organization of proteins, lipids, and other biomolecules, as well as the interactions of cells to form tissues and organs. It incorporates the ubiquitin, glycan, and phosphoinositide codes, among others.
The proteolipid code framework. Not shown: the tears shed developing it.
Figure 2d — Kervin TA, Overduin M. BMC Biol. 2024. doi:10.1186/s12915-024-01849-6
As a scientific theory, the proteolipid code challenges several previous ideas that have, to put it charitably, underperformed. These include the unmodified lipid raft theory, modified lipid raft theories (yes, there were multiple patches — none of them worked), and the picket-and-fence/tiered mesoscale model.
These frameworks fail to capture the full complexity of biological membranes and are inconsistent with thermodynamics — or, as we like to say, they violate the laws of physics and nobody seemed to mind.
The proteolipid code at a glance. Each component earns its keep.
Figure 1a — Overduin M et al. Curr Opin Struct Biol. 2025. doi:10.1016/j.sbi.2025.103061
In Memoriam
Obituaries for Failed Models
They served the field. Sort of. For a while. We're being generous.
The Lipid Raft Hypothesis
1997 – Ongoing DenialCause of death: Thermodynamics
Born from the observation that some lipids cluster together (groundbreaking), the lipid raft hypothesis proposed that cholesterol and sphingolipids form floating platforms in the membrane. Like actual rafts, but less useful for escaping a desert island and more useful for getting papers published. Sadly, rafts turned out to be thermodynamically implausible in living cells — a detail the field cheerfully ignored for two decades. Survived by thousands of citations and an identity crisis.
doi:10.1038/42408Modified Lipid Raft Theories
2006 – Still twitchingCause of death: Patch upon patch upon patch
When the original raft hypothesis started taking on water, the field did what any reasonable community would do: they added epicycles. "Rafts are real, they're just smaller!" "Rafts are real, they're just transient!" "Rafts are real, you just can't see them!" At some point, an invisible, transient, nanoscale entity that can't be directly observed is less a hypothesis and more a shared hallucination.
doi:10.1101/cshperspect.a041395Picket-and-Fence / Tiered Mesoscale
2005 – Quietly retiredCause of death: Incomplete worldview
An admirable attempt to explain membrane organization through cytoskeletal "fences" and anchored protein "pickets." Think of it as a well-intentioned border wall for lipids. While it correctly identified that the cytoskeleton influences membrane dynamics, it forgot about thermodynamics, lipid diversity, protein-lipid coupling, and — one might argue — the membrane itself. Otherwise, great model.
doi:10.1016/j.tibs.2011.08.001
Zone architecture of the proteolipid code. Each zone is a distinct thermodynamic entity. Unlike rafts, these actually exist.
Figure 1c — Overduin M et al. Curr Opin Struct Biol. 2025. doi:10.1016/j.sbi.2025.103061
Chapter II
Lipids: Not Just "Structural" and "Signaling"
For decades, membrane biology operated with a taxonomy of lipid function that would embarrass a toddler's crayon box: structural and signaling. Two categories. For thousands of lipid species. Two.
The proteolipid code calls for a reassessment. Lipids play roles that are far more varied, specific, and — dare we say — interesting:
Each lipid group plays a unique role in organizing membrane components. This is the part where we'd normally say "see our paper for details," but honestly, just saying the word "isleprint" at a conference is worth the look on people's faces alone.
The components in action. Every lipid has a job. Some have several.
Figure 2b — Kervin TA, Overduin M. BMC Biol. 2024. doi:10.1186/s12915-024-01849-6
Chapter III
Codes Within the Code
The proteolipid code doesn't replace other biological codes — it subsumes them. Like a corporate merger, but for biochemistry and with significantly less shareholder value.
| Code | What It Does | Status | Our Honest Assessment |
|---|---|---|---|
| Ubiquitin Code | Tags proteins for degradation, trafficking, signaling | INCORPORATED | The postal service of the cell. Surprisingly reliable. |
| Glycan Code | Cell recognition, immune modulation, protein folding | INCORPORATED | Bewilderingly complex. Glycobiologists seem fine. We worry about them. |
| Phosphoinositide Code | Membrane identity, vesicle trafficking, signaling | INCORPORATED | Seven lipids, infinite drama. Classic. |
| Others | Various | INCORPORATED | We'll get to them. Give us a minute. |
Chapter IV
Universal Scope
Unlike previous models that were suspiciously specific to mammalian cell biology, the proteolipid code is general enough to encompass:
A Necessary Confession
Yes, We Proposed a "Unifying Theory"
We are painfully aware that proposing a unifying framework in biology is roughly as socially acceptable as bringing a guitar to a dinner party. The academic community traditionally greets such ambitions with the warmth of a lipid bilayer at 4°C.
And yet here we are. We've checked the thermodynamics. We've checked them again. We've looked at the data from every domain of life. We've considered that we might be wrong, found it theoretically possible but empirically unlikely, and decided to proceed anyway.
If you disagree, we welcome constructive feedback, spirited debate, and — if absolutely necessary — strongly worded emails written in the passive voice.
* "Largest cellular code" is measured by mass, volume, and number of components. If you have a larger one, congratulations, and also please share your data because we'd love to see it.
Chapter V
What Could This Actually Do?
Our framework could someday — someday, we're managing expectations here — be used for:
🎯 Targeted Membrane Therapies
Design new therapies that control and target membrane zonation. Instead of blasting entire cells, actually understand which membrane zone to talk to.
Confidence: Cautiously optimistic
🧠 Explain How Brains Work
Membranes are fundamental to neural function. If we understand the proteolipid code, we might finally understand brains. This claim is either visionary or delusional. Possibly both.
Confidence: Aspirational
💻 Realistic Simulations of Life
Inform simulations that actually respect thermodynamics. Unlike most of the simulations currently running. We're looking at you, CG models with implicit membranes.
Confidence: Give us a decade
"The membrane is not a sea with rafts. It is not a fence with pickets. It is a code — written in lipids and proteins, read by every cell on earth, and apparently decipherable only by people willing to be laughed at for a while."— Us, probably at a conference, definitely after coffee
