Dock5 also known as DOCK5, is a large (~180 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-A 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 (GEFs) 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. Dock5 is predicted to activate the small G protein Rac

Rac (GTPase)

Rac is a subfamily of the Rho family of GTPases, small signaling G proteins .The subgroup include:*Rac1*Rac2*Rac3*RhoG...

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Function

Dock5 shares significant sequence identity with Dock180, the archetypal member of the DOCK family. It is therefore predicted to partake in similar interactions although this has yet to be demonstrated. Indeed, the function and signalling properties of Dock5 are poorly understood thus far. Dock5 has been identified as a crucial signalling protein in osteoclasts, and suppression of Dock5 expression

Gene expression

Gene expression is the process by which information from a gene is used in the synthesis of a functional gene product. These products are often proteins, but in non-protein coding genes such as ribosomal RNA , transfer RNA or small nuclear RNA genes, the product is a functional RNA...

 with shRNA has been shown to inhibit survival and differentiation

Cellular differentiation

In developmental biology, cellular differentiation is the process by which a less specialized cell becomes a more specialized cell type. Differentiation occurs numerous times during the development of a multicellular organism as the organism changes from a simple zygote to a complex system of...

 of osteoclast precursor cells. In addition, a mutation in Dock5 has been associated with the rupture of murine lens cataract

Cataract

A cataract is a clouding that develops in the crystalline lens of the eye or in its envelope, varying in degree from slight to complete opacity and obstructing the passage of light...

s. In zebrafish Dock5 has been implicated in myoblast fusion

Myogenesis

Myogenesis is the formation of muscular tissue, in particular during embryonic development.Muscle fibers form from the fusion of myoblasts into multi-nucleated fibers . In the early development of an embryo these myoblasts will proliferate if enough fibroblast growth factor is present...

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Further reading