Parvalbumin
Encyclopedia
Parvalbumin is a calcium
-binding albumin protein with low molecular weight (typically 9-11 kDa).
It has three EF hand
motifs and is structurally related to calmodulin
and troponin C
. Parvalbumin is localised in fast-contracting muscles, where its levels are highest, and in the brain and some endocrine tissues.
Parvalbumin is a small, stable protein containing EF-hand type calcium binding sites. It is involved in calcium signaling. Typically, this protein is broken into three domains, domains AB, CD and EF, each individually containing a helix-loop-helix motif. The AB domain houses a two amino-acid deletion in the loop region, whereas domains CD and EF contain the N-terminal and C-terminal, respectively. Calcium binding proteins like parvalbumin play a role in many physiological processes, namely cell-cycle regulation, second messenger production, muscle contraction, organization of microtubules and vision. They have also been found to be in connection with various areas of clinical interest such as Alzheimer’s disease, nervous system disorders, age-related cognitive defects and some forms of cancer.
Parvalbumin is present in GABA
ergic interneuron
s in the nervous system, expressed predominantly by chandelier
and basket cell
s in the cortex. In the cerebellum
, PV is expressed in Purkinje cells and molecular layer interneurons. In the hippocampus
, PV+ interneurons are subdivided into basket, axo-axonic, bistratified, and oriens-lacunosum moleculare (O-LM) cells, each subtype targeting distinct domains of pyramidal cell
s.
PV interneurons' connections are mostly perisomatic (around the cell body of neurons). Most of the PV interneurons are fast-spiking
. They are also thought to give rise to gamma wave
s recorded in EEG
.
PV-expressing interneurons represent approximately 5% of GABA cells in the primate
DLPFC
. Other calcium-binding protein markers are calretinin
(most abundant subtype in DLPFC, about 50%) and calbindin
. Interneurons are also divided into subgroups by the expression of neuropeptides (somatostatin
, neuropeptide Y
, cholecystokinin
).
.
PV has been identified as an allergen
causing seafood allergy
.
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
-binding albumin protein with low molecular weight (typically 9-11 kDa).
It has three EF hand
EF hand
The EF hand is a helix-loop-helix structural domain found in a large family of calcium-binding proteins. The EF-hand motif contains a helix-loop-helix topology, much like the spread thumb and forefinger of the human hand, in which the Ca2+ ions are coordinated by ligands within the loop...
motifs and is structurally related to calmodulin
Calmodulin
Calmodulin is a calcium-binding protein expressed in all eukaryotic cells...
and troponin C
Troponin C
Troponin C is a part of the troponin complex. It contains four calcium-binding EF hands. It is a component of thin filaments . It contains an N lobe and a C lobe. The C lobe serves a structural purpose and binds to the N domain of TnI. The C lobe can bind either Ca2+ or Mg2+...
. Parvalbumin is localised in fast-contracting muscles, where its levels are highest, and in the brain and some endocrine tissues.
Parvalbumin is a small, stable protein containing EF-hand type calcium binding sites. It is involved in calcium signaling. Typically, this protein is broken into three domains, domains AB, CD and EF, each individually containing a helix-loop-helix motif. The AB domain houses a two amino-acid deletion in the loop region, whereas domains CD and EF contain the N-terminal and C-terminal, respectively. Calcium binding proteins like parvalbumin play a role in many physiological processes, namely cell-cycle regulation, second messenger production, muscle contraction, organization of microtubules and vision. They have also been found to be in connection with various areas of clinical interest such as Alzheimer’s disease, nervous system disorders, age-related cognitive defects and some forms of cancer.
Parvalbumin is present in GABA
Gabâ
Gabâ or gabaa, for the people in many parts of the Philippines), is the concept of a non-human and non-divine, imminent retribution. A sort of negative karma, it is generally seen as an evil effect on a person because of their wrongdoings or transgressions...
ergic interneuron
Interneuron
An interneuron is a multipolar neuron which connects afferent neurons and efferent neurons in neural pathways...
s in the nervous system, expressed predominantly by chandelier
Chandelier cell
Chandelier neurons or chandelier cells are a subset of GABA-ergic cortical interneurons. They are described as parvalbumin-containing and fast-spiking to distinguish them from other subtypes of GABAergic neurons. The name comes from the specific shape of their axon arbors, with the terminals...
and basket cell
Basket cell
Basket cells are inhibitory GABAergic interneurons found in several brain regions: the molecular layer of the cerebellum, the hippocampus, and the cortex.-Cerebellum:...
s in the cortex. In the cerebellum
Cerebellum
The cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...
, PV is expressed in Purkinje cells and molecular layer interneurons. In the hippocampus
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
, PV+ interneurons are subdivided into basket, axo-axonic, bistratified, and oriens-lacunosum moleculare (O-LM) cells, each subtype targeting distinct domains of pyramidal cell
Pyramidal cell
Pyramidal neurons are a type of neuron found in areas of the brain including cerebral cortex, the hippocampus, and in the amygdala. Pyramidal neurons are the primary excitation units of the mammalian prefrontal cortex and the corticospinal tract. Pyramidal neurons were first discovered and...
s.
PV interneurons' connections are mostly perisomatic (around the cell body of neurons). Most of the PV interneurons are fast-spiking
Action potential
In physiology, an action potential is a short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, and...
. They are also thought to give rise to gamma wave
Gamma wave
A gamma wave is a pattern of neural oscillation in humans with a frequency between 25 to 100 Hz, though 40 Hz is prototypical.According to a popular theory, gamma waves may be implicated in creating the unity of conscious perception...
s recorded in EEG
EEG
EEG commonly refers to electroencephalography, a measurement of the electrical activity of the brain.EEG may also refer to:* Emperor Entertainment Group, a Hong Kong-based entertainment company...
.
PV-expressing interneurons represent approximately 5% of GABA cells in the primate
Primate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
DLPFC
Dorsolateral prefrontal cortex
The dorsolateral prefrontal cortex , according to a more restricted definition, is roughly equivalent to Brodmann areas 9 and 46. According to a broader definition DL-PFC consists of the lateral portions of Brodmann areas 9 – 12, of areas 45, 46, and the superior part of area 47. These regions...
. Other calcium-binding protein markers are calretinin
Calretinin
Calretinin also known as 29 kDa calbindin is a vitamin D-dependent calcium-binding protein involved in calcium signaling. In humans, the calretinin protein is encoded by the CALB2 gene.- Function :...
(most abundant subtype in DLPFC, about 50%) and calbindin
Calbindin
Calbindin refers to several calcium-binding proteins. They were originally described as vitamin D-dependent calcium-binding proteins in the intestine and kidney in the chick and mammals...
. Interneurons are also divided into subgroups by the expression of neuropeptides (somatostatin
Somatostatin
Somatostatin is a peptide hormone that regulates the endocrine system and affects neurotransmission and cell proliferation via interaction with G-protein-coupled somatostatin receptors and inhibition of the release of numerous secondary hormones.Somatostatin...
, neuropeptide Y
Neuropeptide Y
Neuropeptide Y is a 36-amino acid peptide neurotransmitter found in the brain and autonomic nervous system."NPY has been associated with a number of physiologic processes in the brain, including the regulation of energy balance, memory and learning, and epilepsy." The main effect is increased food...
, cholecystokinin
Cholecystokinin
Cholecystokinin is a peptide hormone of the gastrointestinal system responsible for stimulating the digestion of fat and protein...
).
Role in pathology
Decreased PV and GAD67 expression was found in PV+ GABAergic interneurons in schizophreniaSchizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
.
PV has been identified as an allergen
Allergen
An allergen is any substance that can cause an allergy. In technical terms, an allergen is a non-parasitic antigen capable of stimulating a type-I hypersensitivity reaction in atopic individuals....
causing seafood allergy
Seafood Allergy
Seafood allergy is a type of food allergy. It is a hypersensitivity to dietary substances from shellfish, scaly fish or crustaceans, causing an overreaction of the immune system, which may lead to severe physical symptoms for millions of people. The Asthma and Allergy Foundation of America...
.