Phosphatidylinositol 4-kinase alpha is an
enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...
that in humans is encoded by the ''PI4KA''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
.
Function
This gene encodes a
1-phosphatidylinositol 4-kinase
In enzymology, a 1-phosphatidylinositol 4-kinase () is an enzyme that catalyzes the chemical reaction
:ATP + 1-phosphatidyl-1D-myo-inositol \rightleftharpoons ADP + 1-phosphatidyl-1D-myo-inositol 4-phosphate
Thus, the two substrates of this enz ...
which catalyzes the first committed step in the biosynthesis of
phosphatidylinositol 4,5-bisphosphate
Phosphatidylinositol 4,5-bisphosphate or PtdIns(4,5)''P''2, also known simply as PIP2 or PI(4,5)P2, is a minor phospholipid component of cell membranes. PtdIns(4,5)''P''2 is enriched at the plasma membrane where it is a substrate for a number of ...
. The mammalian PI 4-kinases have been classified into two types, II and III, based on their molecular mass, and modulation by detergent and
adenosine
Adenosine (symbol A) is an organic compound that occurs widely in nature in the form of diverse derivatives. The molecule consists of an adenine attached to a ribose via a β-N9- glycosidic bond. Adenosine is one of the four nucleoside build ...
. Two transcript variants encoding different isoforms have been described for this gene.
Clinical significance
The alpha isoform of PI4KIII plays a role in replication of
hepatitis C virus
The hepatitis C virus (HCV) is a small (55–65 nm in size), enveloped, positive-sense single-stranded RNA virus of the family ''Flaviviridae''. The hepatitis C virus is the cause of hepatitis C and some cancers such as liver cancer ( hepatoc ...
(HCV).
Furthermore, the PI4KA lipid kinase affects HCV replication by altering phosphorylation of the HCV
NS5A
Nonstructural protein 5A (NS5A) is a zinc-binding and proline-rich hydrophilic phosphoprotein that plays a key role in Hepatitis C virus RNA replication. It appears to be a dimeric form without ''trans''-membrane helices.
Structure
NS5A is deri ...
protein.
References
Further reading
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{{Portal bar, Biology, border=no
EC 2.7.1