Chemokine

From Ganfyd

Chemokines are small peptides that have roles in the immune and central nervous system and angiogenesis. They interact with cells through transmembrane, G protein-coupled receptors. There are four major subfamilies. They can be classified by first two of four conserved cysteine residues:

1. CXC chemokines (α-chemokines)
   • Two cysteines are separated by a single amino acid
   • Designated CXXLn many have better known names
   • All map to 4q12-q21 in the order centromere<-- IL-8 --- GCP-2 --- PF4var1 --- NAP-3 --- heterogeneous nuclear ribonucleoprotein A1(not a chemokine) --- PF4 --- PPBP --- CXCL5 --- CXCL3 --- PPBPL2 --- MIP2-alpha -->telomere
     1. ELR subtype
        • Adjacent glu-leu-arg sequence (N-terminal)
        • Chemotactic for neutrophils
     2. Non-ELR subtype
        • No N-terminal glu-leu-arg sequence by the CXC sequence
        • Chemotactic for lymphocytes
2. CC chemokines (β-chemokines)
   • Two cysteines are adjacent
   • Chemoattractants for monocytes, basophils, eosinophils, and T lymphocytes
   • Induce migration of monocytes, NK cells and dendritic cells
   • Designated CCL1-CCL28
   • Ten receptors known
3. C chemokines (γ-chemokines)
   • Lymphotactin (LTN, XCL1, SCM1A, SCYC1, CL-1) - attracts T cell precursors to the thymus.
   • Cytokine SCM-1 beta precursor (XCL2, SCM1B, SCYC2, CL-2)
4. CX3C chemokines (δ-chemokines)
   • Fractalkine is both secreted and a membrane protein serving as both a chemoattractant and as an adhesion molecule.