Lecture 22 – Nuclear Pore, Journey through Membrane Systems
Confocal Laser Scanning Microscopy (CLSM)
• Atype of Fluorescent Microspy that makes use of two pinhole apertures, one at the light source,
the other at the optical lens, to obtain light at precise depths of the cell.
• Using this technique, and fluorescent dyes, one can see Lamin (αLamin B dye), DNA(DAPI
dye, regions of dense DNAare bluer, e.g. heterochromatin) and nuclear pores (αNPC dye,
which stains a protein characteristic to nuclear pores)
3-Dimensional Structural Illumination (3D-SIM)
• Super resolution techniques that allow one to better see the nuclear pores.
• Composed of several nuclear pore proteins (Nup)
• Several Cytoplasmic filaments.
• Nuclear Pores are the gateways to the nucleus.
• The membrane's Cisternal space (Cisternae) is continuous with the lumen of the Endoplasmic
Endoplasmic Reticulum (ER)
• Composed of two types, Rough and Smooth ER (RER and SER).
• RER is the type that is directly attached to the nuclear membrane.
• ER encloses spaces, known as cisterna, which are chambers of cytoplasm isolated from the
main body of cell cytoplasm, basically the inside of the ER.
• Cisternae are continuous with the nuclear intermembrane space.
1 | S y d n e s Sheffield
• On the RER, there are ribosomes embedded in the membrane, many times in groups, making
designs like spirals, groups of ribosomes are called polysomes.
• While RER is arranged in sheet like layers, SER is more tubular.
• SER lacks ribosomes, hence its name.
Discovery of ER
• Keith Porter, using an EM, dried down cells on a thin film, and was able to discern, out of the
mess, a common network found in each cell. This is how ER was named, endoplasmic (within
the cell) reticulum (network).
Function of ER
• RER synthesizes proteins either to be exported, membrane associated or vesicle associated.
• SER has different functions in different cells, it is associated with synthesis of lipids (like
steroids), degradation of various compounds (like barbituates – sedative)