Rnd3 is a small (~21 kDa) signaling

G protein G proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. Their ...

(to be specific, a

GTPase GTPases are a large family of hydrolase enzymes that bind to the nucleotide guanosine triphosphate (GTP) and hydrolyze it to guanosine diphosphate (GDP). The GTP binding and hydrolysis takes place in the highly conserved P-loop "G domain", a ...

), and is a member of the Rnd subgroup of the

Rho family of GTPases The Rho family of GTPases is a family of small (~21 kDa) signaling G proteins, and is a subfamily of the Ras superfamily. The members of the Rho GTPase family have been shown to regulate many aspects of intracellular actin dynamics, and are found ...

. It is encoded by the gene RND3. Like other members of the Rho family of

Ras Ras or RAS may refer to: Arts and media * RAS Records Real Authentic Sound, a reggae record label * Rundfunk Anstalt Südtirol, a south Tyrolese public broadcasting service * Rás 1, an Icelandic radio station * Rás 2, an Icelandic radio stati ...

-related GTPases it regulates the organization of the actin cytoskeleton in response to extracellular growth factors.

Regulation

Most Rho family members cycle between an inactive GDP-bound form and an active GTP-bound form. However, members of the Rnd subgroup of the Rho family are exceptions to this, binding detectably only to GTP, while having low GTPase activity, if any. Instead, Rnd family proteins are regulated through other mechanisms that control their

production Production may refer to: Economics and business * Production (economics) * Production, the act of manufacturing goods * Production, in the outline of industrial organization, the act of making products (goods and services) * Production as a stati ...

degradation Degradation may refer to: Science * Degradation (geology), lowering of a fluvial surface by erosion * Degradation (telecommunications), of an electronic signal * Biodegradation of organic substances by living organisms * Environmental degradatio ...

phosphorylation In chemistry, phosphorylation is the attachment of a phosphate group to a molecule or an ion. This process and its inverse, dephosphorylation, are common in biology and could be driven by natural selection. Text was copied from this source, ...

, and

localization Localization or localisation may refer to: Biology * Localization of function, locating psychological functions in the brain or nervous system; see Linguistic intelligence * Localization of sensation, ability to tell what part of the body is af ...

Interactions

In its GTP-bound form, RhoA exposes regions that allow it to interact with downstream targets. Rnd3 contains a region which is similar to the one RhoA exposes for

interaction Interaction is action that occurs between two or more objects, with broad use in philosophy and the sciences. It may refer to: Science * Interaction hypothesis, a theory of second language acquisition * Interaction (statistics) * Interaction ...

with

ROCK1 ROCK1 is a protein serine/threonine kinase also known as rho-associated, coiled-coil-containing protein kinase 1. Other common names are ROKβ and P160ROCK. ROCK1 is a major downstream effecter of the small GTPase RhoA and is a regulator of the ...

, allowing Rnd3 to compete with RhoA for interaction with ROCK1. By binding to ROCK1, Rnd3 inhibits it from phosphorylating downstream targets necessary for

stress fiber Stress fibers are contractile actin bundles found in non-muscle cells. They are composed of actin (microfilaments) and non-muscle myosin II (NMMII), and also contain various crosslinking proteins, such as α-actinin, to form a highly regulated ...

formation. Rnd3 is also directly involved in controlling RhoA activity through suppression of

PLEKHG5 Pleckstrin homology domain containing, family G member 5 (PLEKHG5) is a protein that in humans is encoded by the ''PLEKHG5'' gene. Eight transcript variants encoding different isoforms have been found for this gene. Function This gene encode ...

and activation of

ARHGAP5 Rho GTPase-activating protein 5 is an enzyme that in humans is encoded by the ''ARHGAP5'' gene. Function Rho GTPase activating protein 5 negatively regulates RHO GTPases, a family that may mediate cytoskeleton changes by stimulating the hydrol ...

. Interaction with

UBXD5 UBX domain-containing protein 11 is a protein that in humans is encoded by the ''UBXN11'' gene. Function This gene encodes a protein with a divergent C-terminal UBX domain. The homologous protein in the rat interacts with members of the Rnd su ...

has also been shown.

Regulation

Interactions

References

Further reading