Lab Members/Photos

Randy Schekman
schekman at berkeley dot edu

A brief biography of Randy on the HHMI website.

News about Randy's 2013 Nobel Prize in Physiology/Medicine (plus lab photos from the day the award was announced).

Photos from the Schekman Symposium held in August 2014.

Liz Alexander-Asher (Executive Assistant)

The Schekman lab is saddened to announce that Liz died suddenly on September 11, 2015. Her skill in coordinating Randy's crazy travel and appointments calendar and providing other administrative support to the lab will be sorely missed.

Renan Aparicio (undergrad)
renan dot aparicio at berkeley dot edu

Several transmembrane proteins have been implicated as genetic risk factors for late-onset Alzheimer's disease (AD).  These proteins interact with and alter the metabolism of the AD-associated amyloid precursor protein (APP), but little is understood about how they influence APP's sorting and the production of amyloid-beta.  I am using the CRISPR-Cas9 system to delete the genes encoding selected AD risk factors and determine how they influence APP sorting and metabolism.

Raj Fadadu (undergrad)
rajfadadu at berkeley dot edu

Extracellular vesicles (EV) have been suggested to play a role in intercellular communication, in many cases by means of miRNA transfer. In order for EV-mediated miRNA transfer to happen, fusion of EVs with the recipient cell must occur. I will implement EV fusion assays in order to study this phenomenon.

Johannes Freitag (post-doc)
johannesf at berkeley dot edu

Peroxisomes are nearly ubiquitous organelles with a variety of metabolic functions including the degradation of fatty acids. I study peroxisome biogenesis in the yeast Saccharomyces cerevisiae. In particular, I am interested in proteins and membranes required for the formation of peroxisomes in the absence of pre-existing peroxisomes. To identify these molecules I will perform genetic screens as well as biochemical reconstitution experiments.

Liang Ge (post-doc)
lge19830626 at gmail dot com

Autophagy is a fundamental intracellular transport pathway, and is considered to be an essential pro-survival process in stress conditions. Although the origin of the autophagosome has been a subject of intense study, it has been difficult to resolve using current imaging techniques. I plan to establish an in vitro autophagosome formation assay to assist in answering this question and to characterize the newly formed autophagosomes, so as to gain insight into autophagy initiation and regulation.

Amita Gorur (grad student)
agorur at lbl dot gov

The molecular underpinnings of procollagen trafficking in cells has confounded cell biologists for decades. Recent work has shown that mono-ubiquitination of Sec31 by the ubiquitin ligase complex Cul3-Klhl12 leads to the formation of enlarged vesicles that drive the secretion of collagen. My goal is to understand the role of these vesicles in collagen transport.

Juliet Hemmati (undergrad)
juliethemmati at berkeley dot edu

The cell’s Coat Protein Complex II (COPII) mediated secretory pathway is responsible for the secretion of collagen, the most abundant protein found in mammals. Through the use of molecular and cell biology techniques, I am studying the role of COPII in the trafficking of procollagen.

Jeremy Henderson (post-doc)
jeremychenderson at gmail dot com

Enthusiasm about sub-micrometer extracellular vesicles (EVs) or so-called exosomes has reached a fever pitch. Despite some recent advances, basic biochemical evidence is still needed to better articulate key aspects of EV biology: packaging of molecular cargo, secretion of vesicular assemblies, and end-fate of extracellularly released material. My work seeks to develop and investigate model interactions between EVs and recipient cell surfaces, to probe for pathways that specifically deliver exosomally packaged material. Additional work will examine sorting and packaging paradigms related to molecules other than miRNAs, which are otherwise enriched in exosomal preparations.

Bob Lesch (lab manager)
lesch at berkeley dot edu

Dawei Liu (undergrad)
dawei.liu at berkeley dot edu

Vesicular trafficking is a fundamental pathway for the material and information flow between organelles, as well as a means to remodel the cellular endomembrane in response to different stresses. Autophagy is a process during which de novo formation of a double-membrane structure, the autophagosome, forms to sequester part of the cytoplasm for delivery to the lysosome for degradation. Recently, molecular machineries and membrane compartments involved in autophagy have also been implied in other fundamental cellular processes, such as unconventional secretion. My project aims to uncover the molecular and membrane connections between vesicular trafficking, autophagy and unconventional secretion by systematic approaches of genetics, biochemistry, imaging and mass spectrometry.

Xiaoman Liu (post-doc)
xiaoman.liu at berkeley dot edu

Exosomes are released by many cells to the extracellular space and may mediate cell-to-cell communication. In addition to proteins, exosomes transport various nucleic acids, such as mRNAs, miRNAs and non-coding RNAs to neighboring cells. However, the mechanism(s) that control the selective sorting of RNAs into exosomes remain incompletely explored. My work is to investigate the underlying mechanism(s) of exosomal RNA selection, which hopefully could pave the way to evaluate the function of exosomes in vivo in a situation that might rely on the delivery of a particular exosomal protein or RNA molecules to specific target cells.

David Melville (post-doc)
afroginawell at gmail dot com

Sar1, one of the five core COPII components, is a highly conserved small GTPase. Mammals have two paralogs of Sar1, SAR1A and SAR1B, which share 90% sequence identity. Despite their high similarity, it has been found that mutations in SAR1B, but not SAR1A, are associated with Chylomicron retention disease in humans. I am using a lipid secreting rat cell line to illuminate the paralog specific functions of Sar1 and the relationship between Sar1 and the COPII outer coat.

Claudia Morales (lab assistant)
moralesacg at yahoo dot com

Lelio Orci (collaborator)
lelio.orci at medecine dot unige dot ch

Sayaka Ri (undergrad)
leesayaka at berkeley dot edu

Coat Protein Complex 2 (COPII) traffics cargo from the ER to the Golgi. I will be studying the role of COPII in trafficking collagen, an example of large cargo. To do this, I will employ the techniques of electron microscopy and molecular biology.

Lior Shtayer (undergrad)
lior.shtayer at berkeley dot edu

Exosomes are known to selectively export protein and RNA cargo and have been recently recognized as a means of signaling in both normal and pathological conditions. I will implement a thiouracil labeling strategy to investigate the exosome RNA cargo and mechanisms of delivery to target cells.

Dan Sirkis (post-doc)
dan dot sirkis at gmail dot com

Several membrane and secreted proteins have been implicated in neurodegenerative disease pathogenesis. Much of the work on these proteins has focused on how they mediate toxicity, but little is known about the mechanisms controlling their export from the Golgi apparatus. I am using cell biological methods and biochemical reconstitution to understand how such proteins are transported from the Golgi to downstream destinations.

Lu Song (visiting scholar)
lusong at berkeley dot edu

Exosomes are small extracellular vesicles that function in the transport of protein and RNA cargoes between cells. Exosomes could affect a range of important biologic processes, including cellular proliferation and differentiation. However, how exosomes play a role in the developmental events especially in the neural fate conversion remains unclear. I will explore the underlying mechanism of the package and delivery of exosome cargoes during neural differentiation.

Vedaja Surapaneni (undergrad)
vedaja.surapaneni at berkeley dot edu

Exosomes are extracellular vesicles that are released when a multivesicular body fuses with the plasma membrane. The role of exosomes in cancer biology is an active field of study. I am using gene editing methods to determine the functional role of miRNA transfer via exosomes in breast cancer model cell lines.

Morayma Temoche-Diaz (grad student)
morayma.temoche-diaz at berkeley dot edu

Exosomes export selectively packaged protein and RNA cargoes to the extracellular space. I am using novel biochemical approaches to investigate how cargoes are specifically sorted into distinct vesicle sub-populations. In the long-term, I am interested in understanding the role of exosome cargoes in normal and cancer cell biology.

Sabrina Washington (Executive Administrative Assistant)
s.washington at berkeley dot edu

Lin Yuan (grad student)
linyuan at berkeley dot edu

Collagen is the most abundant protein in mammals and it functions to maintain tissue integrity. It is secreted by the cell via the COPII mediated secretory pathway. I am interested in learning how the rigid procollagen fibers that are 300nm in length are packaged into COPII vesicles that are typically 60nm in diameter.

Min Zhang (post-doc)
minzhang at berkeley dot edu

Mammalian cells secrete proteins mainly through the conventional ER–Golgi secretory pathway. However, some cytoplasmic proteins are released in an unconventional manner independent of ER and Golgi. Autophagy, a cellular process characterized by de novo formation of double membrane structures for intracellular material degradation, contributes to one aspect of unconventional secretion, such as the secretion of IL-1beta. However, the molecular mechanism of autophagy-mediated protein secretion is unclear. Using IL-1beta as a marker, I plan to establish a cell-free system to uncover the mechanism of autophagy-related unconventional secretion.