Showing papers on "Pore forming protein published in 1988"
TL;DR: One of the major outer membrane proteins of yeast mitochondria was isolated and purified and migrated as a single band with an apparent molecular weight of 30 kDa on a SDS-electrophoretogram.
Abstract: One of the major outer membrane proteins of yeast mitochondria was isolated and purified. It migrated as a single band with an apparent molecular weight of 30 kDa on a SDS-electrophoretogram. When reconstituted in lipid bilayer membranes the protein formed pores with a single channel conductance of 0.45 nS in 0.1 M KCl. The pores had the characteristics of general diffusion pores with an estimated diameter of 1.7 nm. The pore of mitochondrial outer membranes of yeast shared some similarities with the pores formed by mitochondrial and bacterial porins. The pores switched to substates at voltages higher than 20 mV. The possible role of this voltagedependence in the metabolism of mitochondria is discussed.
47 citations
TL;DR: Results indicate that cytolytic cells containing PFP have developed defense mechanisms to inhibit PEP‐mediated cell lysis.
Abstract: Pore-forming protein (perforin, PFP) was isolated from a mouse large granular lymphocyte (LGL) [natural killer (NK-like)] cell line. Purified PFP lysed a variety of mouse tumor cell lines and helper T lymphocyte cell lines. However, LGL and cytotoxic T lymphocyte cell lines were resistant to PFP-mediated cell lysis. The presence of hemolytic activity in the granule was examined in these resistant cell lines. Four out of five of these resistant cell lines had hemolytically active granules. We determined whether NK cells freshly isolated from BALB/c nude mouse spleens were resistant to PFP-mediated cytolysis. Nylon column-passed spleen cells with an enriched content of NK cells exhibited more resistance than whole spleen cells. Moreover, when spleen cells were treated with PFP the remaining live cells showed enriched NK activity suggesting that normal peripheral cells with NK activity are resistant to PFP. These results indicate that cytolytic cells containing PFP have developed defense mechanisms to inhibit PEP-mediated cell lysis.
35 citations
TL;DR: The murine lymphocyte pore-forming protein (PFP) was purified to apparent homogeneity by successive steps of liquid chromatography and amino terminal analysis revealed a tertiary structure for monomeric PFP that is enriched in surface acidic amino acids.
27 citations
TL;DR: It was suggested that heparin potentiates the lytic activity of perforin and acid mucopolysaccharides may actually be involved in target cell lysis by CTL.
Abstract: A cytolytic protein (perforin) was rapidly purified from a cell line of mouse cytotoxic T-lymphocytes (CTL) by DEAE-cellulose, heparin-Sepharose, and phenyl-Sepharose chromatographies. The purified perforin was activated by heparin, the half maximal concentration being 3-10 ng/ml, depending on the calcium concentration. Other acid mucopolysaccharides, such as chondroitin sulfates A and C, keratan polysulfate, and heparin sulfate, also enhanced the lysis of erythrocytes by perforin, but the concentrations required for activation were more than 100-fold higher than that of heparin. Chondroitin, hyaluronic acid, and keratan sulfate, however, had no effect on the perforin activity. It was suggested that heparin potentiates the lytic activity of perforin and acid mucopolysaccharides may actually be involved in target cell lysis by CTL.
4 citations