Kinesin-like protein KIF3A is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
that in humans is encoded by the ''KIF3A''
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
KIF3A is one subunit of the
heterotrimeric motor protein,
kinesin
A kinesin is a protein complex belonging to a class of motor proteins found in eukaryotic cells. Kinesins move along microtubule (MT) filaments and are powered by the hydrolysis of adenosine triphosphate (ATP) (thus kinesins are ATPases, a typ ...
-2, that was initially isolated from sea urchin egg/embryo
cytosol
The cytosol, also known as cytoplasmic matrix or groundplasm, is one of the liquids found inside cells ( intracellular fluid (ICF)). It is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondri ...
using
microtubule
Microtubules are polymers of tubulin that form part of the cytoskeleton and provide structure and shape to eukaryotic cells. Microtubules can be as long as 50 micrometres, as wide as 23 to 27 nanometer, nm and have an inner diameter bet ...
affinity purification.
This motor consists of two kinesin-related subunits (called KIF3A and
KIF3B
Kinesin-like protein KIF3B is a protein that in humans is encoded by the ''KIF3B'' gene. KIF3B is an N-type protein that complexes with two other kinesin proteins to form two-headed anterograde motors. First, KIF3B forms a heterodimer with KIF3A ...
or 3C in vertebrates) and an associated protein (
KAP3), and it transports protein complexes, nucleic acids and organelles towards the "plus" ends of microtubule tracks within cells. Work done in a broad range of eukaryotic cells has revealed that heterotrimeric kinesin-2 is the primary motor protein driving the
intraflagellar transport
Intraflagellar transport (IFT) is a bidirectional motility along axoneme microtubules that is essential for the formation (ciliogenesis) and maintenance of most eukaryotic cilia and flagella. It is thought to be required to build all cilia that as ...
of
tubulin
Tubulin in molecular biology can refer either to the tubulin protein superfamily of globular proteins, or one of the member proteins of that superfamily. α- and β-tubulins polymerize into microtubules, a major component of the eukaryotic cytosk ...
s and other
axonemal building blocks from the base of the ciliary/flagellar axoneme to their site of assembly at the distal tips.
This process is required for cilium assembly/maintenance and
cilium
The cilium (: cilia; ; in Medieval Latin and in anatomy, ''cilium'') is a short hair-like membrane protrusion from many types of eukaryotic cell. (Cilia are absent in bacteria and archaea.) The cilium has the shape of a slender threadlike pr ...
-based signalling which play key roles in various cell and developmental processes. For example, in vertebrate embryos, kinesin-2 function is required for cilia-dependent
nodal flow and the development of left-right asymmetry.
Interactions
KIF3A has been shown to
interact with
MAP3K10
Mitogen-activated protein kinase kinase kinase 10 is an enzyme that in humans is encoded by the ''MAP3K10'' gene.
Function
The protein encoded by this gene is a member of the serine/threonine kinase family. This kinase has been shown to activ ...
.
References
Further reading
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{{Cytoskeletal proteins