View source for Perforin-1

{{Short description|Mammalian protein found in Homo sapiens}}
{{distinguish|Porphyrin}}
{{Infobox_gene}}'''Perforin-1''' Perforin (PRF), encoded by the PRF1 gene, is a pore-forming toxic protein housed in the secretory granules of cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells. Together, these cells are known as cytotoxic lymphocytes (CLs). <ref name=":0">{{Cite journal |last1=Voskoboinik |first1=Ilia |last2=Trapani |first2=Joseph A. |date=2013 |title=Perforinopathy: A Spectrum of Human Immune Disease Caused by Defective Perforin Delivery or Function |journal=Frontiers in Immunology |volume=4 |page=441 |doi=10.3389/fimmu.2013.00441 |doi-access=free |issn=1664-3224 |pmc=3860100 |pmid=24376445}}</ref>

== Discovery ==
Perforin was initially discovered in 1983 and subsequently cloned from an expression library in 1988 using anti-complement C9 antibody cross-reactivity. A sequence comparison showed a notable resemblance between the two proteins in a specific central region, termed the 'membrane attack complex/perforin' (MACPF) domain. <ref>{{Cite journal |last1=Brennan |first1=A J |last2=Chia |first2=J |last3=Trapani |first3=J A |last4=Voskoboinik |first4=I |date=April 2010 |title=Perforin deficiency and susceptibility to cancer |url=https://www.nature.com/articles/cdd2009212 |journal=Cell Death & Differentiation |language=en |volume=17 |issue=4 |pages=607–615 |doi=10.1038/cdd.2009.212 |pmid=20075937 |issn=1350-9047}}</ref>

==Structure and Function==
Purifying perforin is challenging due to its tendency to lose activity and stability in solution, and only recently has a recombinant form been successfully produced.<ref name=":1">{{Cite journal |last1=Pipkin |first1=Matthew E |last2=Lieberman |first2=Judy |date=2007-06-01 |title=Delivering the kiss of death: progress on understanding how perforin works |journal=Current Opinion in Immunology |series=Lymphocyte activation/Lymphocyte effector functions |volume=19 |issue=3 |pages=301–308 |doi=10.1016/j.coi.2007.04.011 |pmid=17433871 |pmc=11484871 |issn=0952-7915}}</ref>

Perforin is a pore forming [[cytolysis|cytolytic]] protein found in the granules of [[cytotoxic T cell|cytotoxic T lymphocytes (CTLs)]] and [[Natural killer cell|natural killer cells (NK cells)]]. Upon [[degranulation]], perforin molecules translocate to the target cell with the help of [[calreticulin]], which works as a chaperone protein to prevent perforin from degrading. Perforin then binds to the target cell's [[plasma membrane]] via membrane phospholipids while phosphatidylcholine binds calcium ions to increase perforin's affinity to the membrane.<ref>Osińska, Iwona et al. "Perforin: an important player in immune response." Central-European journal of immunology vol. 39,1 (2014): 109-15. doi:10.5114/ceji.2014.42135</ref> Perforin oligomerises in a Ca2+ dependent manner to form pores on the target cell. The pore formed allows for the passive diffusion of a family of pro-apoptotic proteases, known as the [[granzyme]]s, into the target cell.<ref name="pmid8770355">{{cite journal |author=[[Joseph Trapani (immunologist)|Trapani JA]] |title=Target cell apoptosis induced by cytotoxic T cells and natural killer cells involves synergy between the pore-forming protein, perforin, and the serine protease, granzyme B |journal=Australian and New Zealand Journal of Medicine |volume=25 |issue= 6 |pages= 793–9 |year= 1996 |pmid= 8770355 |doi= 10.1111/j.1445-5994.1995.tb02883.x}}</ref> The lytic membrane-inserting part of perforin is the [[MACPF]] domain.<ref>{{cite journal |author=Tschopp J|author-link=Jürg Tschopp|author2=Masson D|author3=Stanley KK |title=Structural/functional similarity between proteins involved in complement- and cytotoxic T-lymphocyte-mediated cytolysis |journal=Nature |volume=322 |issue=6082 |pages=831–4 |year=1986 |pmid=2427956 |doi=10.1038/322831a0|bibcode=1986Natur.322..831T |s2cid=4330219 }}</ref> This region shares homology with cholesterol-dependent [[cytolysin]]s from Gram-positive bacteria.<ref name="macpfstructure">{{cite journal |vauthors=Rosado CJ, Buckle AM, Law RH, Butcher RE, Kan WT, Bird CH, Ung K, Browne KA, Baran K, Bashtannyk-Puhalovich TA, Faux NG, Wong W, Porter CJ, Pike RN, Ellisdon AM, Pearce MC, Bottomley SP, Emsley J, Smith AI, Rossjohn J, Hartland EL, Voskoboinik I, Trapani JA, Bird PI, Dunstone MA, Whisstock JC | title = A common fold mediates vertebrate defense and bacterial attack | journal = Science | volume = 317 | issue = 5844 | pages = 1548–51 | year = 2007 | pmid = 17717151 | doi = 10.1126/science.1144706 | bibcode = 2007Sci...317.1548R | s2cid = 20372720 | doi-access = free }}</ref>

The initial concept of a plasma membrane pore model was challenged when research revealed that [[granzyme B]] could undergo [[endocytosis]] independently of perforin. Moreover, experiments demonstrated that [[apoptosis]] could be induced by adding perforin to washed cells that had already endocytosed granzyme B, even in the absence of perforin during the endocytosis process. In light of these findings, Froelich and colleagues suggested that perforin's action might not occur at the plasma membrane as previously thought, but rather at the endosomal membrane.<ref>{{Cite journal |last1=Froelich |first1=Christopher J. |last2=Orth |first2=Kim |last3=Turbov |first3=Jane |last4=Seth |first4=Prem |last5=Gottlieb |first5=Roberta |last6=Babior |first6=Bernard |last7=Shah |first7=Girish M. |last8=Bleackley |first8=R. Christopher |last9=Dixit |first9=Vishva M. |last10=Hanna |first10=William |date=November 1996 |title=New Paradigm for Lymphocyte Granule-mediated Cytotoxicity |journal=Journal of Biological Chemistry |volume=271 |issue=46 |pages=29073–29079 |doi=10.1074/jbc.271.46.29073 |doi-access=free |pmid=8910561 |issn=0021-9258}}</ref> They proposed that perforin likely facilitates the release of granzymes from endosomes by forming pores in the endosomal membrane.<ref name=":1" />

Perforin has structural and functional similarities to [[complement component 9]] (C9). Like C9, this protein creates transmembrane [[tubule]]s and is capable of lysing non-specifically a variety of target cells. This protein is one of the main cytolytic proteins of cytolytic granules, and it is known to be a key effector molecule for T-cell- and natural killer-cell-mediated cytolysis.<ref name="entrez">{{cite web |title=Entrez Gene: PRF1 perforin 1 (pore forming protein) |url=https://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=5551}}</ref> Perforin is thought to act by creating holes in the plasma membrane which triggers an influx of calcium and initiates membrane repair mechanisms. These repair mechanisms bring perforin and granzymes into early endosomes.<ref name="pmid21685908">{{cite journal |vauthors=Thiery J, Keefe D, Boulant S, Boucrot E, Walch M, Martinvalet D, Goping IS, Bleackley RC, Kirchhausen T, Lieberman J |title= Perforin pores in the endosomal membrane trigger the release of endocytosed granzyme B into the cytosol of target cells |journal= Nat. Immunol. |volume= 12 |issue= 8 |pages= 770–7 |year= 2011 |pmid= 21685908 |pmc= 3140544 |doi= 10.1038/ni.2050 }}</ref>

== Clinical Significance ==

=== ''Acute'' presentations of perforinopathy — FHL ===
Around the turn of the 21st century, it was recognized that a total loss of perforin activity leads to a severe, fatal autosomal recessive immunoregulatory disorder in infants, known as [[Hemophagocytic lymphohistiocytosis|familial hemophagocytic lymphohistiocytosis]] (FHL), typically appearing before 12 months of age. This condition can only be treated effectively with a bone marrow transplant from a non-related donor.<ref name=":0" /> 

The pathogenesis involves a sequence of downstream events resulting from the inability of [[Natural killer cell|NK cells]] and CTLs to present functional perforin, thereby failing to kill target cells. Infants affected by this condition typically show symptoms of "classic" [[Hemophagocytic lymphohistiocytosis|familial hemophagocytic lymphohistiocytosis]] (FHL) and meet most or all of the criteria outlined in HLH-2004. Diagnosis is confirmed by reduced NK cell cytotoxicity, as healthy NK cells normally exhibit constitutive, pathogen-independent cytotoxicity, and by identifying mutations in genes such as PRF1, UNC13D, STX11, and STXBP2.<ref name=":0" />

=== ''Sub-acute'' presentations of perforinopathy ===
Sub-acute perforinopathies encompass a diverse array of symptoms, all stemming from a partial ("sub-total") reduction in cytotoxic lymphocyte (CL) activity due to bi-allelic mutations in one of the four previously mentioned genes. In contrast to the acute form, diagnosing sub-acute perforinopathies can be challenging due to their typically milder and more sporadic clinical manifestations, an intermittent disease course, variability in onset age, and their frequent positive response to non-specific immune-suppressive or immune-ablative treatments.<ref name=":0" />

=== ''Chronic'' presentations of perforinopathy ===
Chronic perforinopathies are regarded as a range of immune-related conditions resulting from monoallelic mutations in genes linked to familial hemophagocytic lymphohistiocytosis (FHL). These conditions typically manifest differently from classic FHL and may include conditions like blood cancers and macrophage activation syndrome, particularly in patients with juvenile rheumatoid arthritis. Onset of symptoms usually occurs after the age of 5. Moreover, some research suggests a correlation between variations in the PRF1 gene and the outcome of allogeneic bone marrow transplantation. However, these associations remain controversial, with studies disproving the connection outweighing those supporting it.<ref name=":0" />

==Interactions==
Perforin has been shown to [[protein-protein interaction|interact]] with [[calreticulin]].<ref name="pmid9671507">{{cite journal  |vauthors=Andrin C, Pinkoski MJ, Burns K, etal |title= Interaction between a Ca2+-binding protein calreticulin and perforin, a component of the cytotoxic T-cell granules |journal= Biochemistry |volume= 37 |issue= 29 |pages= 10386–94 |date=July 1998 |pmid= 9671507 |doi= 10.1021/bi980595z }}</ref>

==See also==
* [[Granzyme]]s
* [[Defensin]]
* [[Complement membrane attack complex]]

==References==
{{Reflist}}

==Further reading==
{{refbegin |2}}
* {{cite journal |author=[[Joseph Trapani (immunologist)|Trapani JA]] |title=Target cell apoptosis induced by cytotoxic T cells and natural killer cells involves synergy between the pore-forming protein, perforin, and the serine protease, granzyme B |journal=[[Australian and New Zealand Journal of Medicine]] |volume=25 |issue= 6 |pages= 793–9 |year= 1996 |pmid= 8770355 |doi= 10.1111/j.1445-5994.1995.tb02883.x}}
* {{cite journal  |vauthors=Peitsch MC, Amiguet P, Guy R, etal |title=Localization and molecular modelling of the membrane-inserted domain of the ninth component of human complement and perforin |journal=[[Mol. Immunol.]] |volume=27 |issue= 7 |pages= 589–602 |year= 1990 |pmid= 2395434| doi=10.1016/0161-5890(90)90001-G}}
* {{cite journal |vauthors=Young JD, Hengartner H, Podack ER, Cohn ZA |title=Purification and characterization of a cytolytic pore-forming protein from granules of cloned lymphocytes with natural killer activity |journal=[[Cell (journal)|Cell]] |volume=44 |issue= 6 |pages= 849–59 |year= 1986 |pmid= 2420467| doi=10.1016/0092-8674(86)90007-3|s2cid=30182487 }}
* {{cite journal |vauthors=Young JD, Cohn ZA, Podack ER |title=The ninth component of complement and the pore-forming protein (perforin 1) from cytotoxic T cells: structural, immunological, and functional similarities |journal=[[Science (journal)|Science]] |volume=233 |issue= 4760 |pages= 184–90 |year= 1986 |pmid= 2425429 |doi=10.1126/science.2425429 }}
* {{cite journal |vauthors=Lichtenheld MG, Podack ER |title=Structure of the human perforin gene. A simple gene organization with interesting potential regulatory sequences |journal=[[J. Immunol.]] |volume=143 |issue= 12 |pages= 4267–74 |year= 1990 |doi=10.4049/jimmunol.143.12.4267 |pmid= 2480391 |s2cid=8326644 |doi-access=free }}
* {{cite journal |vauthors=Shinkai Y, Takio K, Okumura K |title=Homology of perforin to the ninth component of complement (C9) |journal=[[Nature (journal)|Nature]] |volume=334 |issue= 6182 |pages= 525–7 |year= 1988 |pmid= 3261391 |doi= 10.1038/334525a0 |bibcode=1988Natur.334..525S |s2cid=4348928 }}
* {{cite journal  |vauthors=Lichtenheld MG, Olsen KJ, Lu P, etal |title=Structure and function of human perforin |journal=Nature |volume=335 |issue= 6189 |pages= 448–51 |year= 1988 |pmid= 3419519 |doi= 10.1038/335448a0 |bibcode=1988Natur.335..448L |s2cid=4359028 }}
* {{cite journal |vauthors=Goebel WS, Schloemer RH, Brahmi Z |title=Target cell-induced perforin mRNA turnover in NK3.3 cells is mediated by multiple elements within the mRNA coding region |journal=Mol. Immunol. |volume=33 |issue= 4–5 |pages= 341–9 |year= 1996 |pmid= 8676885| doi=10.1016/0161-5890(95)00155-7}}
* {{cite journal |vauthors=Nöske K, Bilzer T, Planz O, Stitz L |title=Virus-Specific CD4+ T Cells Eliminate Borna Disease Virus from the Brain via Induction of Cytotoxic CD8+ T Cells |journal=[[J. Virol.]] |volume=72 |issue= 5 |pages= 4387–95 |year= 1998 |pmid= 9557729 |doi= 10.1128/JVI.72.5.4387-4395.1998|pmc=109669 }}
* {{cite journal  |vauthors=Andrin C, Pinkoski MJ, Burns K, etal |title=Interaction between a Ca2+-binding protein calreticulin and perforin, a component of the cytotoxic T-cell granules |journal=[[Biochemistry (journal)|Biochemistry]] |volume=37 |issue= 29 |pages= 10386–94 |year= 1998 |pmid= 9671507 |doi= 10.1021/bi980595z }}
* {{cite journal  |vauthors=Yu CR, Ortaldo JR, Curiel RE, etal |title=Role of a STAT binding site in the regulation of the human perforin promoter |journal=J. Immunol. |volume=162 |issue= 5 |pages= 2785–90 |year= 1999 |doi=10.4049/jimmunol.162.5.2785 |pmid= 10072525 |s2cid=26096007 |doi-access=free }}
* {{cite journal  |vauthors=Stepp SE, Dufourcq-Lagelouse R, Le Deist F, etal |title=Perforin gene defects in familial hemophagocytic lymphohistiocytosis |journal=Science |volume=286 |issue= 5446 |pages= 1957–9 |year= 1999 |pmid= 10583959| doi=10.1126/science.286.5446.1957}}
* {{cite journal  |vauthors=Takahashi T, Nieda M, Koezuka Y, etal |title=Analysis of human V alpha 24+ CD4+ NKT cells activated by alpha-glycosylceramide-pulsed monocyte-derived dendritic cells |journal=J. Immunol. |volume=164 |issue= 9 |pages= 4458–64 |year= 2000 |pmid= 10779745 |doi= 10.4049/jimmunol.164.9.4458|doi-access= free }}
* {{cite journal |vauthors=Badovinac VP, Tvinnereim AR, Harty JT |title=Regulation of antigen-specific CD8+ T cell homeostasis by perforin and interferon-gamma |journal=Science |volume=290 |issue= 5495 |pages= 1354–8 |year= 2000 |pmid= 11082062| doi=10.1126/science.290.5495.1354|bibcode=2000Sci...290.1354B }}
* {{cite journal  |vauthors=Göransdotter Ericson K, Fadeel B, Nilsson-Ardnor S, etal |title=Spectrum of Perforin Gene Mutations in Familial Hemophagocytic Lymphohistiocytosis |journal=[[Am. J. Hum. Genet.]] |volume=68 |issue= 3 |pages= 590–7 |year= 2001 |pmid= 11179007 |doi=10.1086/318796 |pmc=1274472 }}
* {{cite journal  |vauthors=Clementi R, zur Stadt U, Savoldi G, etal |title=Six novel mutations in the PRF1 gene in children with haemophagocytic lymphohistiocytosis |journal=[[J. Med. Genet.]] |volume=38 |issue= 9 |pages= 643–6 |year= 2002 |pmid= 11565555 |doi=10.1136/jmg.38.9.643 |pmc=1734943 }}
* {{cite journal |vauthors=Ambach A, Bonnekoh B, Gollnick H |title=Perforin granule release from cytotoxic lymphocytes ex vivo is inhibited by ciclosporin but not by methotrexate |journal=Skin Pharmacol. Appl. Skin Physiol. |volume=14 |issue= 5 |pages= 249–60 |year= 2001 |pmid= 11586066| doi=10.1159/000056355|s2cid=30142804 }}
{{refend}}

==External links==
* {{MeshName|perforin}}

{{Pore-forming toxins}}

{{NLM}}

[[Category:Programmed cell death]]
[[Category:Proteins]]