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I am professor Marc Friechel.
I'm working at the
Pharmacological Institute,
and I'm heading the Department
of General Pharmacology.
Welcome to my talk with the
title, TRP Channels with Diverse
Permeability Profiles: Regulation
of Blood Pressure and Fertility.
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The TRP class of ion channels
consists of 6 sub-families, which
cover altogether 28 members,
at least in mice.
Each TRP protein consists of six
putative transmembrane domains,
and it is generally believed
that four of such TRP proteins
together form hetero or
homomultimeric channel complexes.
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Most TRP channels are non
selective with a permeability
for calcium of a sodium below 10.
Therefore TRP channels are not
only important for calcium entry
across the plasma
membrane, but play also
an important role in electrogenesis,
regulating the driving force
for calcium entry via other
calcium permeable channels.
This table gives you an overview
about the permeability of channels
formed by individual TRP
proteins of the TRPC, TRPV,
and TRPM sub-family.
It should be emphasized that
most of this information
is based on studies
of heterologously
expressed channel proteins.
And that characteristics
of those channels
may differ significantly from
native channel complexes that exist
in primary cells, since the
ectopically expressed channel
proteins do not necessarily
act in accordance
with the native cellular
context as in primary sets.
Within the TRP family
of cation channels
the highlighted channel
proteins TRPV5 and TRPV6,
as well as TRPM4 and TRPM5, have
distinct characteristic features.
TRPV6 proteins for instance, are
able to form channels that conduct
calcium ions with the
selectivity of calcium
over sodium of about more than 100.
Whereas TRPM4 protein similar
like TRPM5 from cation channels
that selectively conduct
monovalent cations.
