Ribosomal protein S6 kinase, 90kDa, polypeptide 3, also known as RPS6KA3, is an enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 that in humans is encoded by the RPS6KA3 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...

.

Function

This gene encodes a member of the RSK (ribosomal S6 kinase

Ribosomal s6 kinase

In molecular biology, ribosomal s6 kinase is a family of protein kinases involved in signal transduction. There are two subfamilies of rsk, p90rsk, also known as MAPK-activated protein kinase-1 , and p70rsk, also known as S6-H1 Kinase or simply S6 Kinase. There are three variants of p90rsk in...

) family of serine/threonine kinase

Serine/threonine-specific protein kinase

Serine/threonine protein kinases phosphorylate the OH group of serine or threonine .At least 125 of the 500+ human protein kinases are serine/threonine kinases .-Regulation:...

s. This kinase contains 2 non-identical kinase catalytic domains and phosphorylates

Phosphorylation

Phosphorylation is the addition of a phosphate group to a protein or other organic molecule. Phosphorylation activates or deactivates many protein enzymes....

 various substrates, including members of the mitogen-activated kinase

Mitogen-activated protein kinase

Mitogen-activated protein kinases are serine/threonine-specific protein kinases that respond to extracellular stimuli and regulate various cellular activities, such as gene expression, mitosis, differentiation, proliferation, and cell survival/apoptosis.-Activation:MAP kinases are activated...

 (MAPK) signalling pathway

MAPK/ERK pathway

The MAPK/ERK pathway is a chain of proteins in the cell that communicates a signal from a receptor on the surface of the cell to the DNA in the nucleus of the cell. The signal starts when a growth factor binds to the receptor on the cell surface and ends when the DNA in the nucleus expresses a...

. The activity of this protein has been implicated in controlling cell growth and differentiation.

Clinical significance

Mutations in this gene have been associated with Coffin-Lowry syndrome

Coffin-Lowry syndrome

Coffin-Lowry syndrome is a genetic disorder that is X-linked dominant and which causes severe mental problems sometimes associated with abnormalities of growth, cardiac abnormalities, kyphoscoliosis, as well as auditory and visual abnormalities.-History:...

 (CLS).

Interactions

RPS6KA3 has been shown to interact

Protein-protein interaction

Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...

 with CREB-binding protein, MAPK1

MAPK1

Mitogen-activated protein kinase 1, also known as MAPK1, p42MAPK, and ERK2, is an enzyme that in humans is encoded by the MAPK1 gene.- Function :The protein encoded by this gene is a member of the MAP kinase family...

 and PEA15

PEA15

Astrocytic phosphoprotein PEA-15 is a protein that in humans is encoded by the PEA15 gene.PEA15 is a death effector domain -containing protein predominantly expressed in the central nervous system, particularly in astrocytes....

.

External links

• GeneReviews/NCBI/NIH/UW entry on Coffin-Lowry syndrome