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Cathelicidin-related antimicrobial peptides are a family of polypeptides primarily stored in the lysosomes of macrophages and polymorphonuclear leukocytes (PMNs). Cathelicidins serve a critical role in mammalian innate immune defense against invasive bacterial infection.[1] The cathelicidin family of peptides are classified as antimicrobial peptides (AMPs). The AMP family also includes the defensins. Whilst the defensins share common structural features, cathelicidin-related peptides are highly heterogeneous.[1] In humans, its precursor is encoded by the gene CAMP, which is cleaved into the active form LL-37.[2]

External IDsGeneCards: [1]
RefSeq (mRNA)



RefSeq (protein)



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Members of the cathelicidin family of antimicrobial polypeptides are characterized by a highly conserved region (cathelin domain) and a highly variable cathelicidin peptide domain.[1]

Cathelicidin peptides have been isolated from many different species of mammals. Cathelicidins were originally found in neutrophils, but have since been found in many other cells including epithelial cells and macrophages after activation by bacteria, viruses, fungi, or the hormone 1,25-D, which is the hormonally active form of vitamin D.[3]


Mechanism of antimicrobial activityEdit

The general rule of the mechanism triggering cathelicidin action, like that of other antimicrobial peptides, involves the disintegration (damaging and puncturing) of cell membranes of organisms toward which the peptide is active.[4] Cathelicidin rapidly destroys the lipoprotein membranes of microbes enveloped in phagosomes after fusion with lysosomes in macrophages.


Crystal Structure Analysis of the Cathelicidin Motif of Protegrins
Pfam clanCL0121
OPM superfamily209
OPM protein2k6o

Cathelicidins range in size from 12 to 80 amino acid residues and have a wide range of structures.[5] Most cathelicidins are linear peptides with 23-37 amino acid residues, and fold into amphipathic α-helices. Additionally cathelicidins may also be small-sized molecules (12-18 residues) with beta-hairpin structures, stabilized by one or two disulphide bonds. Even larger cathelicidin peptides (39-80 amino acid residues) are also present. These larger cathelicidins display repetitive proline motifs forming extended polyproline-type structures.[1]

The cathelicidin family shares primary sequence homology with the cystatin[6] family of cysteine proteinase inhibitors, although amino acid residues thought to be important in such protease inhibition are usually lacking.

Mammalian orthologsEdit

Cathelicidin peptides have been found in humans, monkeys, mice, rats, rabbits, guinea pigs, pandas, pigs, cattle, frogs, sheep, goats, chickens, and horses.

Currently identified cathelicidins include the following:[1]

  • Human: hCAP-18 (cleaved into LL-37 and FALL-39)
  • Rhesus monkey: RL-37
  • Mice:CRAMP-1/2, (Cathelicidin-related Antimicrobial Peptide[7]
  • Rats: rCRAMP
  • Rabbits: CAP-18
  • Guinea pig: CAP-11
  • Pigs: PR-39, Prophenin, PMAP-23,36,37
  • Cattle: BMAP-27,28,34 (Bovine Myeloid Antimicrobial Peptides); Bac5, Bac7
  • Frogs: cathelicidin-AL (found in Amolops loloensis)[8]
  • Sheep:
  • Goats:
  • Chickens: Four cathelicidins, fowlicidins 1,2,3 and cathelicidin Beta-1 [9]
  • Horses:
  • Pandas:
  • Tasmanian Devil: Saha-CATH5 [10]
  • Salmonids: CATH1 and CATH2

Clinical significanceEdit

Patients with rosacea have elevated levels of cathelicidin and elevated levels of stratum corneum tryptic enzymes (SCTEs). Cathelicidin is cleaved into the antimicrobial peptide LL-37 by both kallikrein 5 and kallikrein 7 serine proteases. Excessive production of LL-37 is suspected to be a contributing cause in all subtypes of Rosacea.[11] Antibiotics have been used in the past to treat rosacea, but antibiotics may only work because they inhibit some SCTEs.[12]

Higher plasma levels of human cathelicidin antimicrobial protein (hCAP18) appear to significantly reduce the risk of death from infection in dialysis patients. Patients with a high level of this protein were 3.7 times more likely to survive kidney dialysis for a year without a fatal infection.[13] The production of cathelicidin is up-regulated by Vitamin D.[14][15]

SAAP-148 (a synthetic antimicrobial and antibiofilm peptide) is a modified version of LL-37 that has enhanced antimicrobial activities compared to LL-37. In particular, SAAP-148 was more efficient in killing bacteria under physiological conditions.[16]

See alsoEdit


  1. ^ a b c d e Zanetti M (January 2004). "Cathelicidins, multifunctional peptides of the innate immunity". Journal of Leukocyte Biology. 75 (1): 39–48. doi:10.1189/jlb.0403147. PMID 12960280.
  2. ^ "Entrez Gene: CAMP cathelicidin antimicrobial peptide".
  3. ^ Liu PT, Stenger S, Li H, Wenzel L, Tan BH, Krutzik SR, Ochoa MT, Schauber J, Wu K, Meinken C, Kamen DL, Wagner M, Bals R, Steinmeyer A, Zügel U, Gallo RL, Eisenberg D, Hewison M, Hollis BW, Adams JS, Bloom BR, Modlin RL (March 2006). "Toll-like receptor triggering of a vitamin D-mediated human antimicrobial response". Science. 311 (5768): 1770–3. doi:10.1126/science.1123933. PMID 16497887.
  4. ^ Kościuczuk EM, Lisowski P, Jarczak J, Strzałkowska N, Jóźwik A, Horbańczuk J, Krzyżewski J, Zwierzchowski L, Bagnicka E (December 2012). "Cathelicidins: family of antimicrobial peptides. A review". Molecular Biology Reports. 39 (12): 10957–70. doi:10.1007/s11033-012-1997-x. PMC 3487008. PMID 23065264.
  5. ^ Gennaro R, Zanetti M (2000). "Structural features and biological activities of the cathelicidin-derived antimicrobial peptides". Biopolymers. 55 (1): 31–49. doi:10.1002/1097-0282(2000)55:1<31::AID-BIP40>3.0.CO;2-9. PMID 10931440.
  6. ^ Zaiou M, Nizet V, Gallo RL (May 2003). "Antimicrobial and protease inhibitory functions of the human cathelicidin (hCAP18/LL-37) prosequence". The Journal of Investigative Dermatology. 120 (5): 810–6. doi:10.1046/j.1523-1747.2003.12132.x. PMID 12713586.
  7. ^ Gallo RL, Kim KJ, Bernfield M, Kozak CA, Zanetti M, Merluzzi L, Gennaro R (May 1997). "Identification of CRAMP, a cathelin-related antimicrobial peptide expressed in the embryonic and adult mouse". The Journal of Biological Chemistry. 272 (20): 13088–93. doi:10.1074/jbc.272.20.13088. PMID 9148921.
  8. ^ Hao X, Yang H, Wei L, Yang S, Zhu W, Ma D, Yu H, Lai R (August 2012). "Amphibian cathelicidin fills the evolutionary gap of cathelicidin in vertebrate". Amino Acids. 43 (2): 677–85. doi:10.1007/s00726-011-1116-7. PMID 22009138.
  9. ^ Achanta M, Sunkara LT, Dai G, Bommineni YR, Jiang W, Zhang G (May 2012). "Tissue expression and developmental regulation of chicken cathelicidin antimicrobial peptides". Journal of Animal Science and Biotechnology. 3 (1): 15. doi:10.1186/2049-1891-3-15. PMC 3436658. PMID 22958518.
  10. ^ Peel E, Cheng Y, Djordjevic JT, Fox S, Sorrell TC, Belov K (October 2016). "Cathelicidins in the Tasmanian devil (Sarcophilus harrisii)". Scientific Reports. 6: 35019. doi:10.1038/srep35019. PMC 5057115. PMID 27725697.
  11. ^ Reinholz M, Ruzicka T, Schauber J (May 2012). "Cathelicidin LL-37: an antimicrobial peptide with a role in inflammatory skin disease". Annals of Dermatology. 24 (2): 126–35. doi:10.5021/ad.2012.24.2.126. PMC 3346901. PMID 22577261.
  12. ^ Yamasaki K, Di Nardo A, Bardan A, Murakami M, Ohtake T, Coda A, Dorschner RA, Bonnart C, Descargues P, Hovnanian A, Morhenn VB, Gallo RL (August 2007). "Increased serine protease activity and cathelicidin promotes skin inflammation in rosacea". Nature Medicine. 13 (8): 975–80. doi:10.1038/nm1616. PMID 17676051.
  13. ^ Gombart AF, Bhan I, Borregaard N, Tamez H, Camargo CA, Koeffler HP, Thadhani R (February 2009). "Low plasma level of cathelicidin antimicrobial peptide (hCAP18) predicts increased infectious disease mortality in patients undergoing hemodialysis". Clinical Infectious Diseases. 48 (4): 418–24. doi:10.1086/596314. PMID 19133797.
  14. ^ Zasloff M (January 2002). "Antimicrobial peptides of multicellular organisms". Nature. 415 (6870): 389–95. doi:10.1038/415389a. PMID 11807545.
  15. ^ Kamen DL, Tangpricha V (May 2010). "Vitamin D and molecular actions on the immune system: modulation of innate and autoimmunity". Journal of Molecular Medicine. 88 (5): 441–50. doi:10.1007/s00109-010-0590-9. PMC 2861286. PMID 20119827.
  16. ^ Breij, Anna de; Riool, Martijn; Cordfunke, Robert A.; Malanovic, Nermina; Boer, Leonie de; Koning, Roman I.; Ravensbergen, Elisabeth; Franken, Marnix; Heijde, Tobias van der (2018-01-10). "The antimicrobial peptide SAAP-148 combats drug-resistant bacteria and biofilms". Science Translational Medicine. 10 (423): eaan4044. doi:10.1126/scitranslmed.aan4044. ISSN 1946-6234. PMID 29321257.

Further readingEdit

External linksEdit

  • PDBe-KB provides an overview of all the structure information available in the PDB for Human Cathelicidin