Transmembrane Signaling

Gangliosides play two major roles in membrane-mediated physiological processes (1) control of transmembrane signaling and (2) mediation of cell-cell or cell-substratum interaction. 

Mediation of Cell-Cell or Cell-Substratum Interaction 

Acknowledgment. I thank Stephen Anderson, Ph.D., for valuable help in preparation of this manuscript. 

Robinson, M. K., Mansson, O., Butcher, E. C., and Magnani, J. L., 1991, A carbohydrate domain common to both sialyl Le and sialyl Le is recognized by the endothelial cell leukocyte adhesion molecule ELAM-1, 7. BioL Chem. 266 14869-14872. 

fiber die Kohlenhydratgruppen des Submaxillarismucins, Hoppe-Seyler s Z. Physiol. Chem. 240 43-54. 

---

Myristic acid may be linked via an amide bond to the a-amino group of the N-terminal glycine residue of selected proteins (Figure 9.18). The reaction is referred to as A -myristoylation and is catalyzed by myristoyl—CoAtprolein N-myris-toyltransferase, known simply as NMT. A -Myristoyl-anchored proteins include the catalytic subunit of cAMP-dependent protein kinase, the ppSff tyrosine kinase, the phosphatase known as calcineurin B, the a-subunit of G proteins (involved in GTP-dependent transmembrane signaling events), and the gag proteins of certain retroviruses, including the FHV-l virus that causes AIDS. 

The hormonal stimulation of adenylyl cyclase is effected by a transmembrane signaling pathway consisting of three components, all membrane-associated. Binding of hormone to the external surface of a hormone receptor causes a conformational change in this transmembrane protein, which in turn stimulates a GTP-binding protein (abbreviated G protein). G proteins are heterotrimeric proteins consisting of a- (45-47 kD), /3- (35 kD), and y- (7-9 kD) subunits. The a-subunit binds GDP or GTP and has an intrinsic, slow... 

Transmembrane Signalling Nuclear Receptors Gluco-mineralocorticoid Receptors... 

Adenylyl Cyclases Guanylyl Cyclases Transmembrane Signalling Cyclic Adenosine Monophosphate Cyclic Guanosine Monophosphate Cyclic Nucleotide-gated Channels Phosphodiesterases... 

Transmembrane Signaling Drag-receptor Interaction G-protein-coupled Receptors Histaminergic System Adenosine Receptois... 

Transmembrane Signaling Nicotinic Receptors Purinergic System... 

Transmembrane Signaling Heterotrimeric G-Proteins Nociception Analgesics... 

Drug Interactions Drug-Receptor Interaction G-protein-coupled Receptors Tolerance and Desensitization Transmembrane Signaling... 

Transmembrane Signaling. Figure 2 Membrane topology of receptors that are associated with effector proteins. Upon binding to their cognate ligands (cyan), receptor proteins without intramolecularly linked effector domain couple via transducer proteins (yellow) to or directly recruit and activate effector proteins (red). Notch receptors release their transducer domains upon proteolytic cleavage, a, p and y stand for G-protein a-, p- and y-subunits, respectively. 

Luttrell LM (2006) Transmembrane signaling by G protein-coupled receptors. Methods Mol Biol 332 3—49... 

Transmembrane Signaling Transport ATPase Transporter Transposon Transverse Tubule Triazenes... 

Membranes are highly viscous, plastic structures. Plasma membranes form closed compartments around cellular protoplasm to separate one cell from another and thus permit cellular individuality. The plasma membrane has selective permeabilities and acts as a barrier, thereby maintaining differences in composition between the inside and outside of the cell. The selective permeabilities are provided mainly by channels and pumps for ions and substrates. The plasma membrane also exchanges material with the extracellular environment by exocytosis and endocytosis, and there are special areas of membrane strucmre—the gap junctions— through which adjacent cells exchange material. In addition, the plasma membrane plays key roles in cellcell interactions and in transmembrane signaling. 

Altieri D. A. Coagulation assembly on leukocytes in transmembrane signaling and cell adhesion. Blood 1993 81,569-79. 

Buckley, N. J. (1990). Molecular pharmacology of cloned muscarinic receptors. In Transmembrane Signalling, Intracellular Messengers and Implications for Drug Development, ed. S. R. Nahorski, pp. 11-30. Chichester John Wiley 8r Sons. 

---