Surfactant protein D rotary shadowed fuzzy ball

Electron microgaphs of lung, Layered intracisternal protein granules in mammalian lung, surfactant proteins A and D, The cell: images, Ultimate order, the cell

Here is an awesome picture in a publication by the following individuals: Martin van Eijk, Chris H.A. van de Lest, Joseph J. Batenburg, Arie B. Vaandrager, Joseph Meschi, Kevan L. Hartshorn, Lambert M.G. van Golde, and Henk P. Haagsman “Porcine Surfactant Protein D Is N-glycosylated in its Carbohydrate Recognition Domain and Is Assembled into Differently Charged Oligomers”, American Journal of Respiratory Cell and Molecular Biology, Vol. 26, No. 6 (2002), pp. 739-747, which I have cropped and repositioned and added a micron marker to.

I am trying to sort out whether the banded protein in the RER of some guinea pig, ferret, and mongrel dog specimens that I have repeatedly observed could be surfactant protein A or perhaps surfactant protein D.  It seems to me that It is possible for the 100 nm periodicity with a central dark band to be surfactant protein D, but because of the relative abundance of SP-A in lung, it seems less likely, though not impossible that it is SP-D.  Another study by: Stefanie M Heinrich and Matthias Griese Assessment of Surfactant Protein A (SP-A) dependent agglutination BMC Pulmonary MedicineBMC series,  shows artificial organization of SP-A, which does the mirror aggregation as I have predicted in my images.  They used streptavidin beads in vitro to accomplish this, and while not showing images that I particularly “believed” the diagram they provided was similar to mine.

Upper image the cruciform tetramer, bottom image the SP-D fuzzy ball.

I think SP-D may not be the protein in the intracisternal RER (granules) profiles in guinea pig in my micrographs, because of the low electron density of the space between the CRDs, that similar area in the SP-A showing a greater relative electron density than seen in the fuzzy ball below.  This is also more reminiscent of the periodicity seen in the langrin/CD 207 protein in Langerhans cells (Birbeck granules), as you will recall that that linear density is electron pale and very electron dense, not more middle density like the intracisternal protein in guinea pig type II cells in these posts.

surfactant_D_rotary_shadowed_SP-D