Biophysical studies of membrane proteins/peptides. Interaction with ...
Biophysical studies of membrane proteins/peptides. Interaction with ...
Biophysical studies of membrane proteins/peptides. Interaction with ...
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
INTERACTION OF HELIX-0 OF THE N-BAR DOMAIN<br />
WITH LIPID BILAYERS<br />
V<br />
INTERACTION OF HELIX-0 OF<br />
THE N-BAR DOMAIN WITH<br />
LIPID MEMBRANES<br />
1. Introduction<br />
Endocytosis is a crucial phenomenon in several cellular processes, such as<br />
receptor recycling and degradation, delivery <strong>of</strong> <strong>membrane</strong>-bound and soluble cargo to<br />
intracellular organelles, and nutrient uptake. Clathrin-mediated endocytosis is likely to<br />
be the best characterized <strong>of</strong> all endocytic pathways, and is responsible for recycling <strong>of</strong><br />
<strong>proteins</strong> from the plasma <strong>membrane</strong>. It is also important in the recycling <strong>of</strong> synaptic<br />
vesicles. A complex assemble <strong>of</strong> clathrin and several other <strong>proteins</strong> drives invagination<br />
<strong>of</strong> the plasma <strong>membrane</strong> and ultimately fission (Dawson et al., 2006). Therefore,<br />
clathrin mediated endocytosis can be separated in two steps. In the first step, the<br />
<strong>membrane</strong> must bend inwards to create a vesicular structure. Following this, the vesicle<br />
is actively pinched <strong>of</strong>f from the <strong>membrane</strong>. The last step is known to be carried out by a<br />
protein called dynamin that polymerizes upon <strong>membrane</strong> binding and arranges into<br />
coiled coats around the neck <strong>of</strong> the nascent vesicles, twisting (through an unknown<br />
mechanism) in response to GTP hydrolysis, leading to fission <strong>of</strong> the vesicle (McMahon<br />
and Gallop, 2005).<br />
In recent years, <strong>studies</strong> have been unravelling the complex network <strong>of</strong> <strong>proteins</strong><br />
involved in clathrin mediated endocytosis. In the end <strong>of</strong> the last decade, De Camilli and<br />
co-workers (Takei et al, 1998; Takei et al, 1999) observed that a protein called<br />
amphiphysin, known to interact <strong>with</strong> dynamin during endocytosis, bounds to spherical<br />
liposomes and induces formation <strong>of</strong> tubules both in the presence and absence <strong>of</strong><br />
137