Peripheral membrane protein

Spectrin, Ankyrin, Other Peripheral Membrane Proteins Help Determine the Shape Flexibility of the Red Blood Cell... 

Membranes are asymmetric. Integral membrane proteins can t be washed off. Peripheral membrane proteins can be washed off. Membrane spanning segments and lipid modification (fatty acylation and prenylation), anchor proteins in a fluid bilayer (Singer fluid mosaic model). 

Proteins that can be removed from membranes by washing them with salt solutions or low pH solutions (disrupts ionic interactions) are called peripheral membrane proteins. Proteins that cannot be removed without disrupting the membrane with detergents are called integral... 

Cysteine string protein (CSP) Cytochrome b561 Peripheral membrane protein that is paimitoylated on >10 cysteines. May have a role in Ca2+ sensitivity of exocytosis. Electron-transport protein required for intravesicular monooxygenases in subsets of secretory vesicles. Required for dopamine- -hydroxylase and peptide amidase activity. 

Rabphilin-3A Peripheral membrane protein that binds to Rab3A and Rab3C as a function of GTP, is substrate for multiple... 

SNAP-25 Syntaxins Paimitoylated peripheral membrane protein that is cleaved by botulinum toxins A and E and binds to syntaxins. Ubiquitous membrane proteins that are cleaved by botulinum toxin Cl and bind to synaptotagmins, SNAP-25,... 

All proteins of the Ras superfamily (Table 1) - with the exception of the Ran protein - undergo a posttranslational modification which introduces at least one hydrophobic modification. These lipid anchors qualify the members of the Ras family as peripheral membrane proteins, which stick into membrane structures from the cytoplasmic side only. 

Fig. 5.1 Schematic drawing of membrane association modes of peptides A Integral membrane proteins (1) major fd coat protein gpVIII of bacteriophage Ml 3 (pdb lfdm), anchored by an 18-residue trans-membrane hydrophobic helix (2) bovine rhodopsin, a 7 trans-membrane domain (G-protein-coupled) receptor (pdb lf88) (3) ion channel peptaibol Chrysospermin C (pdb lee7), and B Peripheral membrane proteins (1) neuro-...

I er-Nielsen, L., Teasdale, R., von Vliet, C., and Gleeson, P. (1999). A novel Golgi-localisation domain domain shared by a class of coiled-coil peripheral membrane proteins. Curr. Biol. 9, 385-388. 

Mu, F. T., et al., EEAl, an early endosome-associated protein. EEAl is a conserved alpha-helical peripheral membrane protein flanked by cysteine fingers and contains a calmodulinbinding IQ motif. J Biol Chcm, 1995, 270(22), 13503-11. 

Figure 1.2 Diagrammatic representation of the plasma membrane. Arrangement of integral and peripheral membrane proteins with the molecular layer of phospholipids is shown.

Peripheral membrane proteins are associated with the head groups of phospholipids or with another integral membrane protein (not shown). 

This heme-dependent peripheral membrane protein is a member of the electron-transport chain, and shuttles electrons between components of Complexes 111 and IV. 

Peripheral membrane proteins interact with the membrane loosely and often reversibly (Figure 4-4). 

Figure 4-4. The domain organization of an integral, transmembrane protein as well as the mechanisms for interaction of proteins with membranes. The numbers illustrate the various ways by which proteins can associate with membranes I, multiple transmembrane domains formed of a-helices 2, a pore-forming structure composed of multiple transmembrane domains 3, a transmembrane protein with a single a-helical membrane-spanning domain 4, a protein bound to the membrane by insertion into the bilayer of a covalently attached fatty acid (from the inside) or 5, a glycosyl phosphatidylinositol anchor (from the outside) 6, a protein composed only of an extracellular domain and a membrane-embedded nonpolar tail 7, a peripheral membrane protein noncova-lently bound to an integral membrane protein.

The water-splitting activity associated with the PSII reaction center has proved exceptionally difficult to purify. A peripheral membrane protein (Mr 33,000) on the... 

A protein of Mr 55,000 in guinea pig milk lipid globule membranes appears to be similar but not identical to the bovine proteins using peptide mapping techniques and solubility in aqueous solutions as comparative criteria (Johnson et al. 1985). This protein is synthesized in a membrane-bound form and becomes progressively solubilized after incorporation into intracellular membranes (Mather et al 1984), a property shared by several other peripheral membrane proteins, e.g., the glycoprotein GP2 in the pancreas (Scheffer et aL 1980). 

Ticketing destinations. We have seen that proteins that contain suitable signal sequences are exported from the cytoplasm while other proteins remain. Some proteins are secreted while others take up residence as integral or peripheral membrane proteins or as soluble proteins within an organelle. 

Schematic illustration of a so-called focal contact, showing how extracellular fibronectin is believed to be indirectly attached to the intracellular cytoskeleton through a transmembrane fibronectin receptor and several other peripheral membrane proteins.

Peripheral membrane proteins only touch the surface of the membrane integral membrane proteins penetrate the lipid double layer - they are partly or fully embedded in it. 

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