PIG-tailed membrane proteins.
Some membrane proteins are associated with the plasma membrane solely through a glycolipid moiety (GPI anchor). The GPI anchor is composed of a core structure of phosphatidylinositol attached to a glycan chain which, in turn, is attached to the C-terminus of the protein. The GPI-anchored protein can be released from the cell surface by the action of GPI-specific phospholipases C and D. In protozoa, GPI anchors represent the predominant mechanism for integrating cell-surface proteins into the lipid bilayer. Addition of a glycolipid anchor to a nascent protein requires a C-terminal hydrophobic signal sequence on the protein which is rapidly exchanged for a pre-assembled anchor. GPI anchors may have roles in protein targeting, cell signalling and in the uptake of small molecules (potocytosis). The human disease 'paroxysmal nocturnal haemoglobinuria' represents a defect in biosynthesis of the GPI anchor. Other lipid post-translational modifications of proteins are also recognized as important in regulating protein function (myristoylation, palmitoylation, prenylation).
Turner
A J
AJ
Department of Biochemistry and Molecular Biology, University of Leeds, U.K.
D000595:Amino Acid Sequence; D000818:Animals; D004705:Endocytosis; D017261:Glycosylphosphatidylinositols / Q000737:chemistry / Q000502:physiology; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008954:Models, Biological; D008969:Molecular Sequence Data; D015398:Signal Transduction
D017261:Glycosylphosphatidylinositols; D008562:Membrane Glycoproteins