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.

Photos from the Schekman Symposium held in August 2014.

Kerensa Broersen (visiting professor)
broersen at berkeley dot edu

The clinically observed hierarchical pattern by which Alzheimer’s disease pathology spreads throughout the brain provokes the question as to which mechanism accounts for the route of transmission. Various means by which pathogenic proteins are secreted by a host cell and taken up by a recipient cell have been suggested, while in particular the non-conventional secretion of tau has attracted interest as providing the most prominent means for a cell to discard of its pathological load. This project aims at investigating the non-conventional secretion of various forms of tau as a potential means of intercellular transport of this protein.

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.

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.

Liang Ma (post-doc)
liangm92 at gmail dot com

Exosomes are small vesicles that are secreted from many metazoan cells, and can convey selected proteins and RNAs to target cells to regulate many cell functions. However, the molecular mechanism of sorting RNA into exosomes is poorly understood. I will investigate how RNAs are specifically sorted into exosomes.

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

Arpita Singhal (undergrad)
arpitasinghal at berkeley dot edu

Causing a stir in the scientific community, exosomes - a type of extracellular vesicle - still remain elusive in nature. Basic biochemical evidence is still needed to understand the key aspects of EV biology.  One of the main functions of EVs is to transfer functional cargo that may alter the status of recipient cells. EVs may also play a strong role in cancer therapeutics. Thus, it is necessary to understand the mechanism through which EVs operate. My research goal is to better understand EV biology, by exploring the interactions between EVs and other cells. By developing and studying interactions between EVs and recipient cell surfaces, I aim to find pathways that can help deliver specific exosomally-packaged material 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.

Sharon Tian (undergrad)
txr97 at berkeley dot edu

I'm investigating the role of autophagy-related protein 8 (Atg8) homologues in autophagosome biogenesis.

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.