Tag Archives: cell biology

Journal Club on Monday, January 7

For our Journal Club on January 7, Yidi Sun presented the following paper:

PtdIns4P synthesis by PI4KIIIα at the plasma membrane and its impact on plasma membrane identity.  Nakatsu F, Baskin JM, Chung J, Tanner LB, Shui G, Lee SY, Pirruccello M, Hao M, Ingolia NT, Wenk MR, De Camilli P.  J Cell Biol. 2012 Dec 10;199(6):1003-16.  PMID:  23229899.

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 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.

Lighting Up Live Cells with Fluorescence (Genetic Engineering & Biotechnology News)

Genetic Engineering & Biotechnology News is out with a Feature Article this week including some comments from David Drubin about targeted genome modification in mammalian cells for fluorescence microscopy studies.

Lighting Up Live Cells with Fluorescence. Christine Herman. GEN. Sep 1, 2012 (Vol. 15, No. 32)

“The difference between taking snapshots of the process and watching a movie is just night and day,” says David Drubin, Ph.D., professor of cell and developmental biology at the University of California, Berkeley, whose lab uses fluorescence to understand the intricate details underlying clathrin-mediated endocytosis.

 

Researchers in David Drubin’s lab at the University of California, Berkeley genetically engineered a human cell line to express endogenous levels of RFP-tagged clathrin light chain A (red) and GFP-tagged dynamin 2 (green) for studying clathrin-mediated endocytosis. The above 3D kymograph of the cell surface, with the time dimension in the z-axis, shows the full lifetime of hundreds of clathrin patches on the membrane, which terminate upon recruitment of dynamin. [Aaron T. Cheng]

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.