≤10,000 VSVG-GFP molecules/PGC
||Mammalian tissue culture cell
||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
||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."
||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)."