Kalirin also known as Huntingtin-associated protein-interacting protein (HAPIP), protein duo (DUO), or serine/threonine-protein kinase with Dbl- and pleckstrin homology domain is a protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 that in humans is encoded by the KALRN gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

. Kalirin was first identified in 1997 as a protein interacting with huntingtin-associated protein 1

Huntingtin-associated protein 1

Huntingtin-associated protein 1 is a protein which in humans is encoded by the HAP1 gene. This protein was found to bind to the mutant huntingtin protein in proportion to the number of glutamines present in the glutamine repeat region....

. Is also known to play an important role in nerve growth and axonal development.

Kalirin is a member of Dbl family of proteins and a Rho guanine nucleotide exchange factor. It is named after the multiple-handed Hindu goddess Kali

KALI

KALI may refer to:* KALI , a radio station licensed to West Covina, California, United States* KALI-FM, a radio station licensed to Santa Ana, California, United States...

 for its ability to interact with numerous other proteins. Kalirin's other name, DUO, comes from the fact that it is 98% identical to rat DUO protein and 80.6% identical to a human protein named TRIO

TRIO (gene)

Triple functional domain protein is a protein that in humans is encoded by the TRIO gene.-Interactions:TRIO has been shown to interact with Filamin and RHOA.-Further reading:...

. Unlike TRIO, which is expressed in numerous tissues, Kalirin isoforms are mainly found in the brain.

Clinical significance

Several isoforms of Kalirin are produced through alternative splicing

Alternative splicing

Alternative splicing is a process by which the exons of the RNA produced by transcription of a gene are reconnected in multiple ways during RNA splicing...

. One of the isoforms, Kalirin-7, was found to be necessary for the remodeling of synapses

Synaptic plasticity

In neuroscience, synaptic plasticity is the ability of the connection, or synapse, between two neurons to change in strength in response to either use or disuse of transmission over synaptic pathways. Plastic change also results from the alteration of the number of receptors located on a synapse...

 in mature cortical neurons and is thought to be important in the development of schizophrenia

Schizophrenia

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...

, as demonstrated by adolescent development of schizophrenia-like symptoms in kalirin knockout mice. Alzheimer's disease

Alzheimer's disease

Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...

may also be linked to kalirin-7.

External links

• Traffic jam in brain causes schizophrenia symptoms
• Architect of Synaptic Plasticity Links Spine Form and Function - Schizophrenia Research Forum, 2007-11-30