Kinesin-like protein KIF3A is a protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 that in humans is encoded by the KIF3A 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

KIF3A is one subunit of the heterotrimeric motor protein, kinesin

Kinesin

A kinesin is a protein belonging to a class of motor proteins found in eukaryotic cells. Kinesins move along microtubule filaments, and are powered by the hydrolysis of ATP . The active movement of kinesins supports several cellular functions including mitosis, meiosis and transport of cellular...

-2, that was initially isolated from sea urchin egg/embryo cytosol

Cytosol

The cytosol or intracellular fluid is the liquid found inside cells, that is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondrion into compartments....

 using microtubule

Microtubule

Microtubules are a component of the cytoskeleton. These rope-like polymers of tubulin can grow as long as 25 micrometers and are highly dynamic. The outer diameter of microtubule is about 25 nm. Microtubules are important for maintaining cell structure, providing platforms for intracellular...

 affinity purification. This motor consists of two kinesin-related subunits (called KIF3A and KIF3B

KIF3B

Kinesin-like protein KIF3B is a protein that in humans is encoded by the KIF3B gene.- Function :The protein encoded by this gene forms a heterotrimeric motor complex with kinesin family member 3A and KAP3 to drive intra-flagellar transport and possibly to aid in chromosome movement during mitosis...

 or 3C in vertebrates) and an associated protein (KAP3

KIFAP3

Kinesin-associated protein 3 is a protein that in humans is encoded by the KIFAP3 gene. It is a non-motor, accesssory subunit which co-oligomerizes with the motor subunits KIF3A and KIF3B or KIF3C, to form heterotrimeric kinesin-2 motor proteins...

), 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 intra-flagellar

Flagellum

A flagellum is a tail-like projection that protrudes from the cell body of certain prokaryotic and eukaryotic cells, and plays the dual role of locomotion and sense organ, being sensitive to chemicals and temperatures outside the cell. There are some notable differences between prokaryotic and...

 transport of tubulin

Tubulin

Tubulin is one of several members of a small family of globular proteins. The most common members of the tubulin family are α-tubulin and β-tubulin, the proteins that make up microtubules. Each has a molecular weight of approximately 55 kiloDaltons. Microtubules are assembled from dimers of α- and...

s and other axonemal

Axoneme

Numerous eukaryotic cells carry whip-like appendages whose inner core consists of a cytoskeletal structure called the axoneme....

 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

Cilium

A cilium is an organelle found in eukaryotic cells. Cilia are slender protuberances that project from the much larger cell body....

-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.