Hippocalcin is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...
that in humans is encoded by the ''HPCA''
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
.
Hippocalcin is a
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...
-binding protein that belongs to the
neuronal calcium sensor Neuronal Calcium Sensor is a large family of proteins which work as calcium dependent molecular switches and includes members like Frequenin (NCS1), recoverin, GCAP, neurocalcin, visinin etc. All the members carry 4 EF hand motifs (out of which only ...
(NCS) family of proteins.
It is expressed in
mammalian
brain
A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a ve ...
s especially in the
hippocampus
The hippocampus (via Latin from Greek , ' seahorse') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, ...
. It possesses a Ca
2+/
myristoyl switch.
Processes
Hippocalcin takes part in the following processes:
* Activation of
PLD1
Phospholipase D1 (PLD1) is an enzyme that in humans is encoded by the ''PLD1'' gene, though analogues are found in plants, fungi, prokaryotes, and even viruses.
History
The possibility of PLD1 was first mentioned in 1947 by authors Hanahan and C ...
and
PLD2
Phospholipase D2 is an enzyme that in humans is encoded by the ''PLD2'' gene.
Function
Phosphatidylcholine (PC)-specific phospholipases D (PLDs) catalyze the hydrolysis of PC to produce phosphatidic acid and choline. Activation of PC-specifi ...
expression
* Inhibition of
apoptosis
*
MAP kinase signalling
* Involved in long term depression in
hippocampal
The hippocampus (via Latin from Greek , 'seahorse') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, an ...
neuron
* Required for normal
spatial learning
In cognitive psychology and neuroscience, spatial memory is a form of memory responsible for the recording and recovery of information needed to plan a course to a location and to recall the location of an object or the occurrence of an event. Sp ...
Interactions
Hippocalcin interacts with following proteins:
* Neuronal apoptosis inhibitory protein (
NAIP)
* Mixed lineage kinase 2 (
MLK2) – MLK2 is myosin light chain kinase 2
* The
b2 adaptin of the
AP2 complex
* Calcium-dependent activator protein for secretion (
CADPS
Calcium-dependent secretion activator 1 is a protein that in humans is encoded by the ''CADPS'' gene.
CADPS encodes a novel neural/ endocrine-specific cytosolic and peripheral membrane protein required for the Ca2+-regulated exocytosis of secreto ...
)
References
Further reading
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External links
NCS proteins
{{Calcium-binding proteins
EF-hand-containing proteins
Hippocampus (brain)