Cell killer proteins

There is a family of proteins (the Bcl-2 family) that can regulate the potential across the inner mitochondrial membrane, and its permeability. Hence, they can influence apoptosis. Some of this family stabilise the inner membrane and maintain the potential, so that they suppress apoptosis. They are known as cell survival molecules (e.g. the proteins, Bcl-2, Bcl-X). Other members of the family destabilise the mitochondria and decrease the membrane potential which facilitates apoptosis. They are known as cell killer proteins (e.g. the proteins, Bax, Bak). The mechanisms by which they have their effects on mitochondria are not known. They are, of course, of considerable interest for the development and control of growth of tumour cells (See Chapter 21). 

Blonder, J., Rodriguez-Galan, M.C., Chan, K.C., Lucas, D.A., Yu, L.R., Conrads, T.P, Issaq, H. J., Young, H.A., Veenstra, T.D. (2004). Analysis of murine natural killer cell microsomal proteins using two-dimensional liquid chromatography coupled to tandem electrospray ionization mass spectrometry. J. Proteome Res. 3, 862-870. 

Antonsson B (2001), Bax and other pro-apoptotic Bcl-2 family killer-proteins and their victim, the mitochondrion, Cell Tissue Res. 306 347-361. 

Cellular differentiation marker 2, a cell adhesion protein found on the surface of T cells and natural killer cells... 

Killer proteins are required for a cell to begin the apoptotic process. 

FIGURE 14.15 Interaction between cytotoxic T cells (killer T cells) and antigen-presenting cells. Foreign peptides that are derived from the cytoplasm of infected cells are displayed on the surface by MHC I proteins. These bind to the T-cell receptor of a killer T cell. A docking protein called CDS helps link the two cells. 

Abe Y, Matsumoto S, Kito K, Ueda N. 2000. Cloning and expression of a novel MAPKK-like protein kinase, lymphokine-activated killer T-cell-originated protein kinase, specifically expressed in the testis and activated lymphoid cells. J Biol Chem 275(28) 21525-21531. 

COPD is a chronic inflammatory disease that results from prolonged and repeated inhalation of particles and gases, chronic (or latent) infection or an interaction of these factors. In many cases, the inflammation persists even when the exposure (in most cases smoking) is stopped. Prominent among the infiltrating leukocytes are neutrophils, CD8+ lymphocytes (Co-receptor for the T-cell receptor. CD8+ is specific for the class IMHC protein. It is expressed on the surface of cytotoxic T-cells and natural killer cells.) and CD68+ monocytic cells (A lysosomal antigen. All cells that rich in... 

Ab, B.K., Kiessling, R., Van, E.J.D., Thole, J.E.. Kumararatne, D.S., Pisa, P., Wondimu. A., Ottenhoff, T.H. (1990). Induction of antigen-specific CD4+ HLA-DR restricted cytotoxic lymphocytes as well as nonspecific nonrestricted killer cells by the recombinant mycobacterial 65 kDa heat shock protein. Eur. J. Immunol. 20, 369-377. 

The natural killer cells (NK) are the host s primary innate immune responders against viral infections. Studies have shown morphine to suppress the cytolytic activity of NK cells (Shavit et al. 2004). In vivo studies carried out in the Indian rhesus macaques looked at chronic morphine administration and SIV the equivalent of HIV in apes. This group concluded that morphine contributed to the pathogenesis of Simian Immunodeficiency Virus (SIV) infection and that this contribution occurred in conjunction with the replication of viral proteins including Tat (Noel and Kumar 2006 Noel et al. 2006). 

Proteins produced by virally infected cells have been shown to interfere with viral replication. They also activate leucocytes that can recognize these infected cells and subsequently kill them. These leucocytes are known as natural killer (NK) cells and the proteins are termed interferons (see also Chapters 3, 5 and 24). 

Apo E, apolipoprotein E CAD, coronary artery disease FKN, fractalkine MHC, major histocompatibility complex MCP-1, monocyte chemoattractant protein 1 MMPs, matrix metalloproteinases NK, natural killer oxLDL, oxidized LDL RANTES, regulated on activation, normal T cell expressed and secreted VSMCs, vascular smooth muscle cells. 

IL-1 (17.5) Monocyte/macrophage, lymphocyte, neutrophil, endothelium, fibroblast keratinocyte Activation of T cells, B cells, natural killer cells, osteoblasts, and endothelium. Induces fever, sleep, anorexia, ACTH release, hepatic acute phase protein synthesis and HSPs. Leads to myocardial depression, hypercoagulability, hypotension/sbock, and death. Simulates production of TNF, IL-6, and IL-8 and stress hormone release. Suppression of cytochrome P-450, thyro-globulin, and lipoprotein synthesis. Procoagulant activity. Antiviral activity. 

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