Number of vesicular stomatitis virus G proteins fused to GFP [VSVG-GFP] in post Golgi carrier [PGC] in COS7 cells

Range ≤10,000 VSVG-GFP molecules/PGC
Organism Mammalian tissue culture cell
Reference Hirschberg K et al., Kinetic analysis of secretory protein traffic and characterization of golgi to plasma membrane transport intermediates in living cells. J Cell Biol. 1998 Dec 14 143(6):1485-503. abstract, p.1494 left column top & bottom paragraphs & p.1501 left column 3rd paragraphPubMed ID9852146
Method Abstract: "Quantitative time-lapse imaging data of single cells expressing the transmembrane protein, vesicular stomatitis virus ts045 G protein fused to green fluorescent protein (VSVG-GFP), were used for kinetic modeling of protein traffic through the various compartments of the secretory pathway. A series of first order rate laws was sufficient to accurately describe VSVG-GFP transport, and provided compartment residence times and rate constants for transport into and out of the Golgi complex and delivery to the plasma membrane."
Comments P.1493 right column bottom paragraph: "PGCs were large and carried significant amounts of VSVG–GFP cargo. An average-sized PGC occupied an area of 1.3 μm^2 corresponding to 32 pixels (with each pixel 0.2 × 0.2 μm), as shown in Fig. 5 D. For comparison, a 100-nm fluorescent bead shown at the same magnification and imaging conditions occupied a single bright pixel (Fig. 5 D, inset). Based on the measured conversion factor between fluorescence and number of VSVG–GFP molecules (Materials and Methods), ∼10,000 VSVG–GFP molecules were contained within an average-sized PGC at peak VSVG–GFP flux out of the Golgi in a cell expressing in the order of 2 × 10^7 VSVG–GFP molecules. A 100-nm vesicle at an equal surface density as found in the PGCs, by comparison, would carry no more than 100 VSVG– GFP molecules." P.1494 left column bottom paragraph: "Quantitation of VSVG–GFP Delivery to the Cell Surface by PGCs: Although a single PGC could carry up to 10,000 VSVG– GFP molecules, [investigators] wanted to quantify the overall contribution to post-Golgi trafficking made by these large structures. In particular, [they] wanted to know what fraction of the total Golgi to plasma membrane transport of VSVG–GFP is by PGCs, rather than by some alternate pathway (for example, by small 100-nm-diam vesicles)."
Entered by Uri M
ID 112597