Dock6 also known as Zir1 is a large (~200 kDa) 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...

 involved in intracellular

Intracellular

Not to be confused with intercellular, meaning "between cells".In cell biology, molecular biology and related fields, the word intracellular means "inside the cell".It is used in contrast to extracellular...

 signalling networks. It is a member of the DOCK-C subfamily of the DOCK

DOCK (protein)

DOCK is a family of related proteins involved in intracellular signalling networks. Studies to date suggest that this family act as guanine nucleotide exchange factors for small G proteins of the Rho family, such as Rac and Cdc42...

 family of guanine nucleotide exchange factor

Guanine nucleotide exchange factor

Guanine nucleotide exchange factors activate monomeric GTPases by stimulating the release of guanosine diphosphate to allow binding of guanosine triphosphate . A variety of unrelated structural domains have been shown to exhibit guanine nucleotide exchange activity...

s which function as activators of small G protein

G protein

G proteins are a family of proteins involved in transmitting chemical signals outside the cell, and causing changes inside the cell. They communicate signals from many hormones, neurotransmitters, and other signaling factors. G protein-coupled receptors are transmembrane receptors...

s.

Discovery

Dock6 was identified as one of a family of proteins which share high sequence similarity with Dock180, the archetypal member of the DOCK family. It has a similar domain arrangement to other DOCK proteins, with a DHR1 domain

DHR1 domain

DHR1 , also known as CZH1 or Docker1, is a protein domain of approximately 200-250 amino acids that is present in the DOCK family of signalling proteins. This domain binds phospholipids and so may assist in recruitment to cellular membranes. There is evidence that this domain may also mediate...

 known in other proteins to bind phospholipids, and a DHR2 domain

DHR2 domain

DHR2 , also known as CZH2 or Docker2, is a protein domain of approximately 450-550 amino acids that is present in the DOCK family of proteins. This domain functions as a guanine nucleotide exchange factor domain for small G proteins of the Rho family...

 containing the GEF activity.

Function

There is currently very little information about the cellular role of this protein. Interestingly, however, Dock6 has been reported to exhibit dual GEF specificity towards the small G proteins Rac1

RAC1

Ras-related C3 botulinum toxin substrate 1 also known as Rac1 is a protein that in humans is encoded by the RAC1 gene. Several alternatively spliced transcript variants of this gene have been described, but the full-length nature of some of these variants has not been determined.- Function :Rac1 is...

 and Cdc42

CDC42

Cell division control protein 42 homolog also known as CDC42 is a protein involved in regulation of the cell cycle. In humans, CDC42 is encoded by the CDC42 gene.- Function :...

. It is the only DOCK family member reported to activate both of these G proteins. The same study also showed that transfection

Transfection

Transfection is the process of deliberately introducing nucleic acids into cells. The term is used notably for non-viral methods in eukaryotic cells...

 of the Dock6 DHR2 domain into N1E-115 neuroblastoma

Neuroblastoma

Neuroblastoma is the most common extracranial solid cancer in childhood and the most common cancer in infancy, with an annual incidence of about 650 cases per year in the US , and 100 cases per year in the UK . Close to 50 percent of neuroblastoma cases occur in children younger than two years old...

 cells promoted Rac- and Cdc42-dependent neurite

Neurite

A neurite refers to any projection from the cell body of a neuron. This projection can be either an axon or a dendrite. The term is frequently used when speaking of immature or developing neurons, especially of cells in culture, because it can be difficult to tell axons from dendrites before...

outgrowth, although the physiological significance of this has yet to be demonstrated.

Further reading