Janus kinase 2

From Biology-Online Dictionary | Biology-Online Dictionary



A protein tyrosine kinase that is responsible in signaling type II cytokine receptor family.


Janus kinase 2 is a member oftyrosine kinase family that mapped to chromosome 9p24.1 where the gene encodes 1,132 amino acids that shares 95% sequence similarity to rat and pig. It is associated to the prolactin receptor and it is activated by tyrosine phosphorylation upon prolactin binding to prolactin receptor. It is more expressly intact in N-terminal domain that binds endoplasmic reticulum to uphold its cell surface expression.

Janus kinase 2 is located in nucleus of hematopoietic cells that is directly phosphorylates tyrosine 41 on histone H3 in human. It offers directives in making proteins that encourages growth and division of cells where it is part of signaling pathway known as JAK/STAT pathway which enable to transmit chemical signals from outside the cell to the cellnucleus. Moreover it is significant for controlling the production of blood cells from hematopoietic stem cells wherein these cells found in the bone marrow that has a potential to build up red blood cells, white blood cells and platelets.

Somatic mutation in the Janus kinase 2 genes is associated with thrombocythemia, a disorder typify by an enlarged number of platelets in the blood that is responsible for blood clotting wherein mutation occurs when building blocks amino acid valine is replaced by phenylalanine at position 617 in the protein.

Gene name: JAK2

Protein name: Tyrosine-protein kinase JAK2

See also:

Protein kinase