Membrane nanotube

Not to be confused with nanotube membrane.

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A High resolution 3D live-cell fluorescence image of a NT (white arrow) connecting two primary mesothelial cells one hour after plating on a collagen I coated glass cover slide. To facilitate detection, cell membranes were stained with WGA Alexa Fluor® 488. Scale bar: 20 µm.
BDepiction of a NT (black arrow) between two cells with scanning electron microscopy one hour after cell plating. Scale bar: 10 µm.
C F-actin staining by fluorescently labeled phalloidin showing actin being present in NTs between individual HPMCs (white arrow). Scale bar: 20 µm.
D Scanning electron microscope picture of a substrate-associated filopodia-like extension as potential NT precursor (black arrowhead). The insert shows a fluorescence microscopic image of substrate associated filopodia-like protrusions approaching a neighboring cell (white arrowhead). Scale bar: 2 µm.

The term Membrane nanotubes, membrane nanotubules or cytoneme has been applied to protrusions that extend from the plasma membrane that enable different animal cells to touch over long distances, sometimes over 100 μm between T cells.

Two types of structures have been called nanotubes. The first type are less than 0.7 micrometres in diameter, contain actin and carry portions of plasma membrane between cells in both directions. The second type are larger (>0.7 μm), contain both actin and microtubules and can carry components of the cytoplasm between cells, such as vesicles and organelles.

These structures may be involved in cell-to-cell communication, transfer of nucleic acids between cells in a tissue, and the spread of pathogens or toxins such as HIV and prions. Membrane nanotubes were first described in a 1999 Cell article examining the development of Drosophila melanogaster wing imaginal discs. More recently, a Science article published in 2004 described structures that connected various types of immune cell together, as well as connections between cells in tissue culture.

Structures, called plasmodesmata, have been identified that do function as channels that interconnect plant cells and stromules interconnect plastids.

Vesicular transport in membrane nanotubes has been modeled utilizing a continuum approach.

External links

• Hans-Hermann Gerdes Research Group - The laboratory that first observed membrane nanotubes