Biological complexity: vesicle membranes (Introduction)

by David Turell , Friday, July 10, 2015, 16:00 (3424 days ago) @ David Turell

Vesicles transport material in cells and have a complex membrane, different in different types of vesicles:-http://phys.org/news/2015-07-cell-machinery-complex-coat.html-"Vesicles are responsible for transporting molecules between the different compartments within a cell and also for bringing material into cells from outside. There are several types of vesicle: each has a specific type of coat which is made up of different proteins and assembles onto a membrane surrounding the vesicle.-"The EMBL team has been taking a close look at a coat called COPI. This surrounds vesicles that move material around within the Golgi apparatus and to the endoplasmic reticulum (ER) - these are regions of the cell where proteins are made and modified in preparation for transport to the cell surface.-"What the images revealed was surprising: unlike other types of vesicle, where the coat is thought to be made from proteins assembled in different layers - each with a specific function - around the vesicle membrane, the EMBL team observed that the proteins in the COPI coat all intertwine together in one big layer, which is curved to fit around the membrane. More precisely, the COPI coat is made of a repetition of building blocks, called "triads", that contain all the important functional elements organised in a precise 3D structure.-"'Our images showed us how the proteins that make up the coat are arranged and it was surprising to discover how different COPI is from, for example, clathrin or COPII coated vesicles," adds Svetlana Dodonova, co-author of the paper. "Our next step will be to try to find out how this coat forms and binds to the vesicle membrane and how it arranges itself into such complex shapes.'" -My usual comment: the more complexity is shown, the less likely for a chance development of life.