PADGEM (GMP140) is a component of Weibel-Palade bodies of human endothelial cells

PADGEM protein (PADGEM), also known as GMP140, is a platelet alpha- granule membrane protein that is translocated to the external membrane after platelet activation. Although the biosynthesis of this protein was originally thought to be confined to megakaryocytes, the synthesis of PADGEM in endothelial cells was recently demonstrated (McEver et al: Blood 70:1974a, 1987). We now describe the subcellular localization of this protein in endothelial cells. Immunofluorescence staining of permeabilized human umbilical vein endothelial cells with KC4, a well characterized monoclonal antibody to PADGEM, showed positively stained elongated structures similar in distribution and shape to Weibel-Palade bodies. Their identity as Weibel-Palade bodies was confirmed by double label immunofluorescence using KC4 and a polyclonal antiserum to von Willebrand factor (vWf), a protein known to be specifically stored in these organelles. All Weibel-Palade bodies were found to contain PADGEM. In contrast to strong perinuclear staining produced with anti- vWf antibodies, no significant perinuclear staining was obtained with KC4, indicating that relatively little PADGEM is present in the endoplasmic reticulum and in the Golgi apparatus. In endothelial cells treated with secretagogues that stimulate vWf release the elongated structures positive for PADGEM disappeared, further identifying these structures as Weibel-Palade bodies. This observation extends the parallels between Weibel-Palade bodies and alpha-granules and suggests a possible functional association between vWf and PADGEM.     

BUILDING THE FOUNDATION OF EXCELLENCE IN HEART FAILURE NURSING

This column contains the presidential address presented during the Third Annual Meeting of the American Association of Heart Failure Nurses on June 28, 2007, in San Diego, California, titled "Building the Foundation of Excellence in Heart Failure Nursing."     

Regulation of the glial fibrillary acidic protein, beta actin and prion protein mRNAs during brain development in mouse.

Developmental regulation in mRNAs of three brain proteins has been investigated by Northern blot evaluation in C57BL/6 mice. The mRNAs of two cytoskeletal components, glial fibrillary acidic protein (GFAP) and beta actin, varied significantly, and differently, during brain development (0-56 days postnatal). The beta actin mRNAs peaked at day 1 after a slight increase, then dropped rapidly during the first 15 days postnatal, and thereafter remained at a level which was strictly maintained throughout development and adulthood. Conversely, the GFAP mRNAs increased during the first two weeks after birth (astroglial proliferation), and then slightly declined until the adult stage (astroglial cell differentiation). The prion protein (PrP) mRNAs were detectable as soon as birth, and increased 4-fold during brain maturation. Then, during the adult life, the GFAP and PrP mRNAs did not change markedly. Nevertheless, slight but significant increases in the mRNA levels of both GFAP and PrP were observed at older stages (360 days). These results are analysed in the light of the implications of PrP and GFAP in scrapie infection models.     

Creating a professional practice environment on a shoestring

Did you ever think, “If we just had a little money we could…”? The current health care environment is wrought with financial stressors that can be overwhelming and take up most of our time. Such stress can limit the development of a professional practice environment if you let it. How do you not only survive but thrive in this financial climate?