The biochemistry of cell adhesion and communication (Introduction)

by David Turell , Friday, December 18, 2015, 02:01 (3045 days ago)

We have discussed inter-cellular communication. This article shows how a series of molecular cascade reactions tell a cell it has adhered to its neighbor and receives communication to act upon:-http://www.mechanobio.info/modules/go-0007229-"Integrins are proteins that function mechanically, by attaching the cell cytoskeleton to the extracellular matrix (ECM), and biochemically, by sensing whether adhesion has occurred. The integrin family of proteins consists of alpha and beta subtypes, which form transmembrane heterodimers. Integrins function as adhesion receptors for extracellular ligands and transduce biochemical signals into the cell, through downstream effector proteins. Remarkably, they function bidirectionally, meaning they can transmit information both outside-in and inside-out.-***-"For integrin to function as a bidirectional signal transmitter, 
 
1) Integrins undergo a process called activation, during which conformational changes expose the headpiece (?I and hybrid domain) for ligand binding [36, 37, 38, 39]. This can be initiated by the binding of adaptor proteins and/or ligands. - 2) Adaptor proteins bind to the integrin cytoplasmic domains, thereby connecting integrin to the cytoskeleton.- 3) Integrins microcluster laterally for efficient ligand binding. - "Upon activation, integrins are capable of triggering a variety of signal transduction cascades. The combination of ? and ? subtypes, for example, will affect different in vivo functions. As demonstrated by knockout mouse studies, and highlighted in the table below, these include cell behaviour and tissue organization."-Comment: A highly complex biochemistry article, but what it says is cells communicate and adhere thru a series of molecular cascade reactions. All of this easily follows instructional information organization, using the natural functional reactions of protein molecules. Shapiro et al. work at the single cell level, and their discussion only covers that level of biochemistry.