Parvalbumins

Parvalbumins are a family of low molecular weight, calcium-binding proteins found in muscle and brain tissues of vertebrates. They belong to the superfamily of EF-hand calcium-binding proteins, characterized by a specific structural motif that allows them to bind calcium ions. Parvalbumins are highly conserved across a wide range of species, suggesting an important and fundamental biological role.

In muscle, parvalbumins are abundant in fast-twitch muscle fibers. Their primary function is to bind calcium ions released from the sarcoplasmic reticulum during muscle contraction and to facilitate their rapid reuptake. This rapid calcium buffering mechanism contributes to the fast relaxation speed of these muscle fibers, enabling quick and efficient movements.

In the brain, parvalbumins are primarily expressed in specific types of interneurons, particularly those that utilize the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). These parvalbumin-positive interneurons play a crucial role in regulating neuronal excitability and synchronizing neural activity. Dysregulation of parvalbumin expression or function in the brain has been implicated in various neurological and psychiatric disorders, including epilepsy, schizophrenia, and autism spectrum disorder. The precise mechanisms by which parvalbumins influence neuronal function are still an active area of research.