For our Journal Club on June 3, Daphné Dambournet presented the following paper:
Divergent modes for cargo-mediated control of clathrin-coated pit dynamics. Soohoo AL, Puthenveedu MA. Mol Biol Cell. 2013 Jun;24(11):1725-34. PMID: 23536704.
Model for divergent modes of cargo-mediated control of endocytosis by signaling receptors.
Yidi Sun‘s new paper is out now as an electronic publication ahead of print in the Journal of Cell Science. Congratulations to Yidi on her great work! The abstract is below. The PDF can be downloaded from JCS here.
The functions of anionic phospholipids during clathrin-mediated endocytosis site initiation and vesicle formation. Sun Y, Drubin DG. J Cell Sci. 2012 Oct 24. PMID: 23097040.
Abstract
Anionic phospholipids PI(4,5)P(2) and phosphatidylserine (PS) are enriched in the cytosolic leaflet of the plasma membrane where endocytic sites form. In this study, we investigated the roles of PI(4,5)P(2) and PS in clathrin-mediated endocytosis (CME) site initiation and vesicle formation in Saccharomyces cerevisiae. Live-cell imaging of endocytic protein dynamics in an mss4(ts) mutant, which has severely reduced PI(4,5)P(2) levels, revealed that PI(4,5)P(2) is required for endocytic membrane invagination but is less important for endocytic site initiation. We also demonstrated that in various deletion mutants of genes encoding components of the Rcy1-Ypt31/32 GTPase pathway, endocytic proteins dynamically assemble not only on the plasma membrane but also on intracellular membrane compartments, which are likely derived from early endosomes. In rcy1Δ cells, fluorescent biosensors indicated that PI(4,5)P(2) only localized to the plasma membrane while PS localized to both the plasma membrane and intracellular membranes. Furthermore, we found that polarized endocytic patch establishment is defective in the PS-deficient cho1Δ mutant. We propose that PS is important for directing endocytic proteins to the plasma membrane and that PI(4,5)P(2) is required to facilitate endocytic membrane invagination.
For our Journal Club on October 15, Jay Ryoo presented the following paper:
The first five seconds in the life of a clathrin-coated pit. Cocucci E, Aguet F, Boulant S, Kirchhausen T. Cell. 2012 Aug 3;150(3):495-507. PMID: 22863004.
Schematic representation of the experimental setup and computational analysis
The Drubin/Barnes Lab would like to congratulate Rebecca Lu who passed her qualifying exam on Wednesday, April 18!
Our note to Rebecca reads: “Congrats! We used to like you! We still do! But we used to, too!”
Here we recount the epic saga of Rebecca’s Ph.D qualification:
After she wrote her proposal, her chair asked her to rewrite it. Rebecca is smarter than Randy Schekman though. She just made a copy.
Rebecca brought food for her committee, and Doug Koshland said, ‘I’m gonna have a donut. Does anyone want one?’ That’s when Rebecca realized that a Qualifying Exam is like some weird quiz where your committee reveals the answers before asking their questions.
During Rebecca’s exam, her committee didn’t ask her a question for 30 minutes. That would have been a REALLY long question, after all.
Rebecca closed her eyes a lot during her Qual. She wasn’t sleeping. She just drew a picture of Randy handing her the Nobel Prize on the back of her eyelids.
You can’t please all the people all the time. Fortunately, all those people weren’t at Rebecca’s Qualifying Exam.
When her exam was over, Randy said, “Guess what. You passed.” Rebecca told Randy, “Dude, you gotta give me time to guess. If you’re gonna quiz me, you must insert a pause in there.”
Akemi Kunibe was the last grad student in the Drubin/Barnes Lab to pass her Qual. She’s smart. She was a tough act to follow. Rebecca will be an especially hard act to follow, cuz when she finished her Qual, she took all of the dry-erase markers with her.
Rebecca doesn’t know the meaning of the word “fail.” And that is kinda worse than not passing in a way, if you think about it. She’s a Ph.D candidate, but she still doesn’t understand simple words.
Congratulations Rebecca Lu! And thank you Mitch Hedberg for the jokes!
For our next Journal Club, Christa Cortesio will present the following paper:
Distinct and separable activities of the endocytic clathrin-coat components Fcho1/2 and AP-2 in developmental patterning. Umasankar PK, Sanker S, Thieman JR, Chakraborty S, Wendland B, Tsang M, Traub LM. Nat Cell Biol. 2012 Apr 8. doi: 10.1038/ncb2473. PMID: 22484487.
Interaction diagram for FCHO1/2 and select endocytic pioneer coat components. Presumptive contacts are indicated with dotted lines.