Congratulations to Yidi Sun on her new paper!

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.

Journal Club on Monday, April 30

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.

Lillie joined the Drubin/Barnes Lab!

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:

Rebecca Lu is qualified!

The Drubin/Barnes Lab would like to congratulate Rebecca Lu who passed her qualifying exam on Wednesday, April 18!

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!

Journal Club on Monday, April 16

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.