For our next Journal Club, Lillie Cohn will present the following paper:
Reconstitution of clathrin-coated bud and vesicle formation with minimal components. Dannhauser PN, Ungewickell EJ. Nat Cell Biol. 2012 Apr 22;14(6):634-9. PMID: 22522172.
Ultrathin section of H6-ΔANTH-AP180328–896-coated liposomes that were incubated with clathrin at 4 °C (c) or 37 °C
For our next Journal Club, Yansong Miao will present the following paper:
An actin-dependent mechanism for long-range vesicle transport. Schuh M. Nat Cell Biol. 2011 Oct 9;13(12):1431-6. PMID: 21983562.
Mechanism of directional vesicle transport
Yidi Sun‘s new paper is out now as an electronic publication ahead of print in the journal Molecular Biology of the Cell. Congratulations to Yidi on her great work! The abstract is below. The PDF can be downloaded from MBoC here.
Orm protein phosphoregulation mediates transient sphingolipid biosynthesis response to heat stress via the Pkh-Ypk and Cdc55-PP2A pathways. Sun Y, Miao Y, Yamane Y, Zhang C, Shokat KM, Takematsu H, Kozutsumi Y, Drubin DG. Mol Biol Cell. 2012 Apr 25. PMID: 22535525.
Abstract
Sphingoid intermediates accumulate in response to a variety of stresses, including heat, and trigger cellular responses. However, the mechanism by which stress affects sphingolipid biosynthesis has yet to be identified. Recent studies in yeast suggested that sphingolipid biosynthesis is regulated through phosphorylation of the Orm proteins, which in humans are potential risk factors for childhood asthma. Here, we demonstrate that Orm phosphorylation status is highly responsive to sphingoid bases. We also demonstrate by monitoring temporal changes in Orm phosphorylation and sphingoid base production in cells inhibited for Ypk1 protein kinase activity, that Ypk1 transmits heat stress signals to the sphingolipid biosynthesis pathway via Orm phosphorylation. Our data indicate that heat-induced sphingolipid biosynthesis in turn triggers Orm protein dephosphorylation, making the induction transient. We identified Cdc55-PP2A (protein phosphatase 2A) as a key phosphatase that counteracts Ypk1 activity in Orm mediated sphingolipid biosynthesis regulation. In total, our study reveals a mechanism through which the conserved Pkh-Ypk kinase cascade and Cdc55-PP2A facilitate rapid, transient sphingolipid production in response to heat stress through Orm protein phosphoregulation. We propose that this mechanism serves as the basis for how Orm phosphoregulation controls sphingolipid biosynthesis in response to stress in a kinetically coupled manner.
A feedback regulation pathway in which Orm protein phosphorylation dynamics rapidly and precisely regulate sphingolipid biosynthesis in response to heat stress. See the text for a description.
For our next Journal Club, Rebecca Lu will present the following paper:
Membrane Fission Is Promoted by Insertion of Amphipathic Helices and Is Restricted by Crescent BAR Domains. Boucrot E, Pick A, Camdere G, Liska N, Evergren E, McMahon HT, Kozlov MM. Cell. 2012 Mar 30;149(1):124-36. PMID: 22464325.
Graphical abstract.
The Drubin/Barnes Yeast and HeLa Cell Manufacturing Company is excited to welcome Lillie Cohn as a new graduate student in the lab! Lillie is a first year in the Molecular and Cell Biology program at UC-Berkeley. Her proposed thesis project is “The Meaning of Life.” On this occasion, let us pause to consider these wise words of the sage Philosoraptor:
Philosoraptor asks “what if finding the meaning of life is the meaning of life?”
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.
For our next Journal Club, Sun Hae Hong will present the following paper:
Influence of synaptic vesicle position on release probability and exocytotic fusion mode. Park H, Li Y, Tsien RW. Science. 2012 Mar 16;335(6074):1362-6. PMID: 22345401.
For our next Journal Club, Eric Lewellyn will present the following paper:
Distinct roles for F-BAR proteins Cdc15p and Bzz1p in actin polymerization at sites of endocytosis in fission yeast. Arasada R, Pollard TD. Curr Biol. 2011 Sep 13;21(17):1450-9. PMID: 21885283
For our last Journal Club, Itziar Benitez-Ibarlucea presented the following paper:
Cytoplasmic dynein moves through uncoordinated stepping of the AAA+ ring domains. DeWitt MA, Chang AY, Combs PA, Yildiz A. Science. 2012 Jan 13;335(6065):221-5. PMID: 22157083