Aquaporin
By Ryan Osgood and Mackenzie Blinn
What they are
• Aquaporin is a protein embedded in the cell membrane in
order to regulate the flow of water
• Water needs to move in and out of a cell, and this is facilitated
by aquaporins (water channels)
• The presence of these water channels increases the
permeability to water of the cell membrane
• These channels are allocated in all kingdoms of life including
bacteria, plants, and mammals
• 13 in mammals, 6 in kidney
• In plants- 4 families
Used for
• Industrial water treatment
• Regulates flow of water in organisms, particularly in
the kidney.
Who discovered them
• In 1992 Peter Agre at John
Hopkins University reported
his unintentional discovery of
aquaporin, he earned a Nobel
Prize for his discovery in 2003
.
• In 2000 Stroud’s lab at UCSF
succeeded in solving the first
high resolution structure of an
aquaporin by using x-ray
crystallography
Primary Structure
• Used for water reabsorption
• Found in kidney
• We can see its primary
structure because of the
amino acid linear sequence
• Simple proteins- AQP
monomer has 6x helical
domains
Secondary Structure
• 6 trans membrane helices in a
RH Bundle- it forms a
tetrameter
• Early evolutionary event
• Used for water reabsorption in
response to ADH (a hormone)
• We can see its secondary
structure because of the alphahelices
Tertiary Structure
• Found in kidney and
medullary collecting duct
• Used for water reabsorption
and glycerol permeability
• We can see its tertiary because
of the tightness of the helixes
folded in one compact globule.
Quaternary Structure
• Used for water reabsorption
• Found in kidney
More on that…
• Some membranes are more permeable than others.
RBC’s, kidney tubules
• AQP 1 was reported in 1992.
Diseases
• Several diseases such as congenital cataracts and
nephrogenic diabetes insipidus are relate to
mutations in aquaporins, also fluid transport, brain
swelling, strokes, meningities, multiple sclerosis.
• A small number of people are found with a
deficiency of aquaporins and they generally seem
healthy, but they have a defect in the ability to
concentrate solutes in urine and to conserve water
when deprived of drinking water
Bibliography
• http://www.ks.uiuc.edu/Research/aquaporins/
• http://www.bionaid.us/research.htm
• http://www.aquaporins.org/disease.htm
• http://www.hopkinsmedicine.org/press/2003/octo
ber/031008a.htm
• http://en.wikipedia.org/wiki/Aquaporin