Membrane dynamics and permeability

Abstract

The surface of cells is a repository of a wide variety of receptors that enable cells to sense their surroundings and to respond appropriately. Some receptors are recognized by enveloped viruses that bind to the cell surface and fuse with it to release the capsid into the cytoplasm of the target cell. Surface components are also involved in immune reactions and in the social behaviour of cells in their organisation into tissues and organs. The plasma membrane represents an important site of attack by pathogens many of which produce toxins that introduce pores into the membrane allowing leakage of the cell contents. The translocation of ions and other solutes through channels is the means by which cell membranes create a selectively permeable barrier allowing compartmentation of cellular processes and coordination of a variety of physiological functions. A gathering of distinguished researchers in the field of membrane dynamics and permeability took place under the auspices of the London Membrane Group and the Cell Surface Research Fund at the Royal Society on September 8, 1995 (Fig. 1) to discuss recent developments in the subject. Another purpose was to mark the occasion of the retirement of Professor Charles Pasternak from St George's Hospital Medical School where he founded the Deparment of Biochemistry more than 20 years ago. One of the remarkable aspects of the meeting was that the contributors were all numbered amongst his former students and colleagues. The topics of the symposium divided into membrane dynamics where the mechanisms of surface receptor and glucose transporter recycling were considered together with the role of cyclic nucleotide messengers in mediating cell movement. Cell surface functions in disease considered the identity of surface features of cells concerned with malignancy and infection. The final section was devoted to a consideration of the mechanisms whereby ions and solutes move through channels and pores in membranes. The treatment ranged from theoretical aspects and modelling to facilitated diffusion processes associated with genetic disorders and infection. As editor of the symposium papers I have been impressed by how well they integrate into the theme of the meeting. That such a broad group of topics can be so encompassed is testimony to the wide ranging interests and expertise of the