PTPRN2

Protein tyrosine phosphatase, receptor type, N polypeptide 2
Available structures
PDB Ortholog search: PDBe, RCSB
Identifiers
SymbolsPTPRN2 ; IA-2beta; IAR; ICAAR; PTPRP; R-PTP-N2
External IDsOMIM: 601698 MGI: 107418 HomoloGene: 2134 IUPHAR: 1862 GeneCards: PTPRN2 Gene
EC number3.1.3.48
RNA expression pattern
More reference expression data
Orthologs
SpeciesHumanMouse
Entrez579919276
EnsemblENSG00000155093ENSMUSG00000056553
UniProtQ92932P80560
RefSeq (mRNA)NM_002847NM_011215
RefSeq (protein)NP_002838NP_035345
Location (UCSC)Chr 7:
157.33 – 158.38 Mb		Chr 12:
116.49 – 117.28 Mb
PubMed search

Receptor-type tyrosine-protein phosphatase N2 (R-PTP-N2) also known as islet cell autoantigen-related protein (ICAAR) and phogrin is an enzyme that in humans is encoded by the PTPRN2 gene.[1][2][3] PTPRN and PTPRN2 (this gene) are both found to be major autoantigens associated with insulin-dependent diabetes mellitus.[3]

Function

Due to a close similarity in the gene sequences, the protein encoded by this gene has traditionally been considered a member of the protein tyrosine phosphatase (PTP) family. PTPs are known to be signaling molecules that regulate a variety of cellular processes including cell growth, differentiation, mitotic cycle, and oncogenic transformation. However, recent research has shown that the PTPRN2 mouse homolog, known as phogrin, phosphorylates the lipid phosphatidylinositol rather than tyrosine. Specifically, phogrin was shown to act upon phosphatidylinositol 3-phosphate and Phosphatidylinositol 4,5-diphosphate, whereas it has never been observed acting upon tyrosine.[4] PTPRN2 should, therefore, be more accurately considered a PIPase rather than a PTPase. Phosphorylated forms of phosphatidylinositol (PI) are called phosphoinositides and play important roles in lipid signaling, cell signaling and membrane trafficking.

The protein produced by PTPRN2 possesses an extracellular region, a single transmembrane region, and a single intracellular catalytic domain, and thus represents a receptor-type PTP. The catalytic domain of this PTP is most closely related to PTPRN, also known as IA-2.[3]

Gene

Three alternatively spliced transcript variants of this gene, which encode distinct proteins, have been reported.[3]

Interactions

PTPRN2 has been shown to interact with: CKAP5,[5] SPTBN4,[6] and UBQLN4.[7]

Clinical significance

R-PTP-N2 functions as an autoantigen in diabetes mellitus type 1.[8][9]

References

  1. ↑ Smith PD, Barker KT, Wang J, Lu YJ, Shipley J, Crompton MR (Jan 1997). "ICAAR, a novel member of a new family of transmembrane, tyrosine phosphatase-like proteins". Biochem Biophys Res Commun 229 (2): 402–11. doi:10.1006/bbrc.1996.1817. PMID 8954911.
  2. ↑ Li Q, Borovitskaya AE, DeSilva MG, Wasserfall C, Maclaren NK, Notkins AL, Lan MS (Sep 1997). "Autoantigens in insulin-dependent diabetes mellitus: molecular cloning and characterization of human IA-2 beta". Proc Assoc Am Physicians 109 (4): 429–39. PMID 9220540.
  3. ↑ 3.0 3.1 3.2 3.3 "Entrez Gene: PTPRN2 protein tyrosine phosphatase, receptor type, N polypeptide 2".
  4. ↑ Caromile LA, Oganesian A, Coats SA, Seifert RA, Bowen-Pope DF (April 2010). "The neurosecretory vesicle protein phogrin functions as a phosphatidylinositol phosphatase to regulate insulin secretion". J. Biol. Chem. 285 (14): 10487–96. doi:10.1074/jbc.M109.066563. PMC 2856256. PMID 20097759.
  5. ↑ Nakayama M, Kikuno R, Ohara O (November 2002). "Protein-protein interactions between large proteins: two-hybrid screening using a functionally classified library composed of long cDNAs". Genome Res. 12 (11): 1773–84. doi:10.1101/gr.406902. PMC 187542. PMID 12421765.
  6. ↑ Berghs S, Aggujaro D, Dirkx R, Maksimova E, Stabach P, Hermel JM, Zhang JP, Philbrick W, Slepnev V, Ort T, Solimena M (November 2000). "betaIV spectrin, a new spectrin localized at axon initial segments and nodes of ranvier in the central and peripheral nervous system". J. Cell Biol. 151 (5): 985–1002. doi:10.1083/jcb.151.5.985. PMC 2174349. PMID 11086001.
  7. ↑ Lim J, Hao T, Shaw C, Patel AJ, Szabó G, Rual JF, Fisk CJ, Li N, Smolyar A, Hill DE, Barabási AL, Vidal M, Zoghbi HY (May 2006). "A protein-protein interaction network for human inherited ataxias and disorders of Purkinje cell degeneration". Cell 125 (4): 801–14. doi:10.1016/j.cell.2006.03.032. PMID 16713569.
  8. ↑ Lu J, Li Q, Xie H, Chen ZJ, Borovitskaya AE, Maclaren NK, Notkins AL, Lan MS (March 1996). "Identification of a second transmembrane protein tyrosine phosphatase, IA-2beta, as an autoantigen in insulin-dependent diabetes mellitus: precursor of the 37-kDa tryptic fragment". Proc. Natl. Acad. Sci. U.S.A. 93 (6): 2307–11. doi:10.1073/pnas.93.6.2307. PMC 39791. PMID 8637868.
  9. ↑ Pietropaolo M, Hutton JC, Eisenbarth GS (February 1997). "Protein tyrosine phosphatase-like proteins: link with IDDM". Diabetes Care 20 (2): 208–14. doi:10.2337/diacare.20.2.208. PMID 9118776.

Further reading

  • Lan MS, Lu J, Goto Y, Notkins AL (1994). "Molecular cloning and identification of a receptor-type protein tyrosine phosphatase, IA-2, from human insulinoma.". DNA Cell Biol. 13 (5): 505–14. doi:10.1089/dna.1994.13.505. PMID 8024693.
  • Cui L, Yu WP, DeAizpurua HJ et al. (1996). "Cloning and characterization of islet cell antigen-related protein-tyrosine phosphatase (PTP), a novel receptor-like PTP and autoantigen in insulin-dependent diabetes.". J. Biol. Chem. 271 (40): 24817–23. doi:10.1074/jbc.271.40.24817. PMID 8798755.
  • Kawasaki E, Hutton JC, Eisenbarth GS (1996). "Molecular cloning and characterization of the human transmembrane protein tyrosine phosphatase homologue, phogrin, an autoantigen of type 1 diabetes.". Biochem. Biophys. Res. Commun. 227 (2): 440–7. doi:10.1006/bbrc.1996.1526. PMID 8878534.
  • Schmidli RS, Colman PG, Cui L et al. (1998). "Antibodies to the protein tyrosine phosphatases IAR and IA-2 are associated with progression to insulin-dependent diabetes (IDDM) in first-degree relatives at-risk for IDDM.". Autoimmunity 28 (1): 15–23. doi:10.3109/08916939808993841. PMID 9754810.
  • van den Maagdenberg AM, Schepens JT, Schepens MT et al. (1999). "Assignment of Ptprn2, the gene encoding receptor-type protein tyrosine phosphatase IA-2beta, a major autoantigen in insulin-dependent diabetes mellitus, to mouse chromosome region 12F.". Cytogenet. Cell Genet. 82 (3-4): 153–5. doi:10.1159/000015090. PMID 9858807.
  • Berghs S, Aggujaro D, Dirkx R et al. (2001). "betaIV spectrin, a new spectrin localized at axon initial segments and nodes of ranvier in the central and peripheral nervous system.". J. Cell Biol. 151 (5): 985–1002. doi:10.1083/jcb.151.5.985. PMC 2174349. PMID 11086001.
  • Kubosaki A, Gross S, Miura J et al. (2004). "Targeted disruption of the IA-2beta gene causes glucose intolerance and impairs insulin secretion but does not prevent the development of diabetes in NOD mice.". Diabetes 53 (7): 1684–91. doi:10.2337/diabetes.53.7.1684. PMID 15220191.
  • Lim J, Hao T, Shaw C et al. (2006). "A protein-protein interaction network for human inherited ataxias and disorders of Purkinje cell degeneration.". Cell 125 (4): 801–14. doi:10.1016/j.cell.2006.03.032. PMID 16713569.