WITHDRAWN: The sorting nexin requirement of the Vps68 recycling signal is context dependent

The authors withdrew this manuscript because their original claim that the sorting nexin requirement for Vps68 recycling is context-dependent was incorrect, as overexpression artifacts and misattributed gene functions obscured the true retromer-dependent nature of the process, which has since been corrected in a new publication.

The Gist

Imagine a busy kitchen (the cell) where a specific chef, named Vps68, is responsible for delivering important ingredients to the pantry (the vacuole). Once the chef drops off the ingredients, they need to be sent back to the kitchen counter to get more work done. This "return trip" is called recycling.

For a long time, the author of this paper thought they had discovered a special rule about how this chef gets sent back. They believed the chef needed a specific type of helper (a "sorting nexin") to get the return ticket, but only in certain situations. They thought the rule was tricky and depended on the context.

However, the author has realized they made a big mistake and is officially taking the paper back.

Here is what actually happened, explained simply:

1. The "Too Much Chef" Problem

The author tried to watch the chef (Vps68) by giving him a giant, glowing backpack (a fluorescent tag called sfGFP). But they accidentally gave the kitchen five times too many chefs wearing these backpacks.

• The Analogy: Imagine trying to watch a single delivery driver navigate a city, but you suddenly flood the streets with 500 identical drivers. They all get stuck in traffic jams at the city gates (the vacuolar membrane).
• The Result: Because there were so many "glowing chefs" stuck at the gate, the author couldn't see that the normal "return bus" (called the retromer) was actually doing its job. The traffic jam hid the fact that the bus was working perfectly. When the author removed the bus in their experiment, they didn't see any difference because the traffic jam was already blocking everything anyway.

2. The "Double Trouble" Mix-up

The author also thought a different character, named Dcr2, was involved in the recycling process. They deleted the "Dcr2" instruction manual and saw the recycling break.

• The Analogy: It turns out the "Dcr2" instruction manual was printed on the same piece of paper as the "Vps38" manual, just on the back side. When the author tore up the "Dcr2" page, they accidentally tore up the "Vps38" page too.
• The Result: The recycling didn't break because Dcr2 was gone; it broke because Vps38 (a crucial part of the machinery) was missing. The author blamed the wrong person.

The Conclusion

The author is saying: "We got it wrong."

• The rule about the "context-dependent helper" is false.
• The real rule is simple: Vps68 always needs the "retromer" bus to get recycled.
• The confusion was caused by having too many chefs and accidentally breaking the wrong part of the machine.

Because the original paper was based on these misunderstandings, the author is asking everyone to stop citing it as if it were true. They have already published a corrected version of the story that explains the real, simple mechanics of how the chef gets his return ticket.

Technical Summary

Based on the text provided, here is a detailed technical summary of the manuscript. It is important to note that this document is a withdrawal statement rather than a standard research article; therefore, the "results" and "contributions" described below refer to the errors identified and the corrections made, rather than the original (flawed) findings of the withdrawn paper.

1. Problem Statement

The original manuscript, titled "The sorting nexin requirement of the Vps68 recycling signal is context dependent," proposed a specific mechanism for the recycling of the protein Vps68. The central hypothesis was that the requirement for sorting nexins in Vps68 recycling was context-dependent, implying that the retromer complex (which includes sorting nexins) was not strictly necessary for this process under all conditions.

2. Methodology and Source of Error

The author, Ralf Kölling, identified that the conclusions of the original study were based on experimental artifacts caused by specific methodological choices:

• Overexpression Artifact: The study utilized an expression construct where sfGFP-Vps68 was overexpressed approximately 5-fold.
• Consequence: This massive overexpression caused the accumulation of sfGFP-Vps68 at the vacuolar membrane. This accumulation physically obscured the phenotypic effects of deleting the retromer complex, leading to the false conclusion that retromer was not required for Vps68 recycling.
• Genetic Overlap Confusion: The study investigated the role of Dcr2 in Vps68 recycling. However, the DCR2 open reading frame (ORF) partially overlaps with the VPS38 gene (which codes for a subunit of the PI-3 kinase complex). The observed phenotypes in the dcr2 deletion strain were actually due to the simultaneous loss of Vps38 function, not Dcr2.

3. Key Findings (Corrected)

The withdrawal statement clarifies the actual biological reality, overturning the original paper's claims:

• Retromer Dependence: Vps68 recycling is strictly retromer-dependent. The original claim that this requirement was "context-dependent" was incorrect.
• Dcr2 Independence: Dcr2 is not involved in Vps68 recycling. The phenotypes previously attributed to Dcr2 loss were entirely attributable to the loss of Vps38 function due to the overlapping gene structure.
• Mechanism Clarification: The accumulation of Vps68 at the vacuole in the original study was an artifact of overexpression, masking the true trafficking pathway.

4. Key Contributions

While the original paper's conclusions were retracted, the withdrawal statement itself provides critical contributions to the field by:

• Correcting the Scientific Record: Explicitly identifying the overexpression artifact and the gene overlap issue that led to the erroneous conclusions.
• Preventing Misinformation: Ensuring that the scientific community does not cite the flawed manuscript as evidence for context-dependent sorting nexin requirements or Dcr2 involvement in Vps68 recycling.
• Providing the Corrected Version: Directing researchers to the corrected manuscript published in Biology Open (DOI: 10.1242/bio.062518), which presumably contains the accurate data and conclusions.

5. Significance

The significance of this document lies in its role as a self-correction mechanism in science:

• Scientific Integrity: It demonstrates the author's commitment to accuracy by voluntarily withdrawing a paper when new results (likely from lower-expression systems or better genetic controls) proved the central hypothesis incorrect.
• Clarification of Trafficking Pathways: It ensures that future research on yeast endosomal sorting, specifically regarding Vps68, retromer, and PI-3 kinase complexes, is built on the correct premise that Vps68 recycling is retromer-dependent and independent of Dcr2.
• Citation Guidance: The author explicitly requests that the withdrawn work not be cited as a reference for the project, preventing the propagation of the initial errors in future literature.

Conclusion:
This document serves as a formal retraction and correction notice. It invalidates the original claim that Vps68 recycling is context-dependent and clarifies that the process is retromer-dependent, while also correcting the misattribution of phenotypes to Dcr2 instead of Vps38. Researchers should refer to the corrected publication in Biology Open for accurate data.