DHR2 also known as CZH2 or Docker2, is a protein domain

Protein domain

A protein domain is a part of protein sequence and structure that can evolve, function, and exist independently of the rest of the protein chain. Each domain forms a compact three-dimensional structure and often can be independently stable and folded. Many proteins consist of several structural...

 of approximately 450-550 amino acids that is present in 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 proteins. This domain functions as a 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...

 (GEF) domain for 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 of the Rho family. DHR2 domains bear no significant similarity to the well described DH domain

RhoGEF domain

RhoGEF domain is a structural domain of guanine nucleotide exchange factors for Rho/Rac/Cdc42-like GTPases. It is also called "Dbl-homologous" domain.-Human proteins containing this domain :...

 (Dbl homologous domain) present in other RhoGEFs such as Vav

Vav (protein)

Vav is a family of proteins involved in cell signalling. They act as guanine nucleotide exchange factors for small G proteins of the Rho family. GEF activity is mediated via module of tandem DH-PH domains. Vav proteins also appear to exhibit GEF-independent functions.There are three members of...

, P-Rex and 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:...

. Indeed, the most divergent mammalian DHR2 domains share only 16-17% sequence similarity.