adaptor protein complex sigma subunits


Summary: A family of small adaptin protein complex subunits of approximately 19 KDa in size.

Top Publications

  1. Kirchhausen T, Davis A, Frucht S, Greco B, Payne G, Tubb B. AP17 and AP19, the mammalian small chains of the clathrin-associated protein complexes show homology to Yap17p, their putative homolog in yeast. J Biol Chem. 1991;266:11153-7 pubmed
    ..The yeast sequence predicts Yap17p, a protein with 147 amino acids and a Mr of 17,373 that is slightly more related to the mammalian AP17 chain than to its AP19 counterpart. ..
  2. Tarpey P, Stevens C, Teague J, Edkins S, O Meara S, Avis T, et al. Mutations in the gene encoding the Sigma 2 subunit of the adaptor protein 1 complex, AP1S2, cause X-linked mental retardation. Am J Hum Genet. 2006;79:1119-24 pubmed
    ..AP1S2 is the first reported XLMR gene that encodes a protein directly involved in the assembly of endocytic vesicles...
  3. Ballarati L, Cereda A, Caselli R, Maitz S, Russo S, Selicorni A, et al. Deletion of the AP1S2 gene in a child with psychomotor delay and hypotonia. Eur J Med Genet. 2012;55:124-7 pubmed publisher
    ..The clinical features of our patient are quite similar to those reported in male patients carrying point mutations, thus suggesting that point mutations and deletions of the AP1S2 gene lead to a recognisable XLMR phenotype in males...
  4. Borck G, Molla Herman A, Boddaert N, Encha Razavi F, Philippe A, Robel L, et al. Clinical, cellular, and neuropathological consequences of AP1S2 mutations: further delineation of a recognizable X-linked mental retardation syndrome. Hum Mutat. 2008;29:966-74 pubmed publisher
  5. Roca R, Stiefel V, Puigdomenech P. Characterization of the sequence coding for the clathrin coat assembly protein AP17 (sigma2) associated with the plasma membrane from Zea mays and constitutive expression of its gene. Gene. 1998;208:67-72 pubmed
    ..The AP17 protein is encoded in maize by a single gene, and its mRNA accumulates in all the organs studied. In the immature embryo, it displays a pattern of expression typical of constitutively expressed genes. ..
  6. Maldonado Mendoza I, Nessler C. Molecular characterization of the AP19 gene family in Arabidopsis thaliana: components of the Golgi AP-1 clathrin assembly protein complex. Plant Mol Biol. 1997;35:865-72 pubmed
    ..Constitutive transcription of AAP19-1 was confirmed in transgenic Arabidopsis seedlings and plants containing an AAP19-1 promoter::beta-glucuronidase (GUS) fusion by ribonuclease protection assays and GUS histochemical staining. ..
  7. Watanabe T, Shimizu F, Nagata M, Takaichi A, Fujiwara T, Nakamura Y, et al. Cloning, expression pattern and mapping to 12p 13.2 --> p13.1 of CLAPS3, a gene encoding a novel clathrin-adaptor small chain. Cytogenet Cell Genet. 1996;73:214-7 pubmed
    ..Northern-blot analysis revealed expression of a 1.35-kb transcript in all human tissues examined. This gene was mapped to chromosome bands 12p13.2 --> p13.1 by FISH. ..
  8. Winterpacht A, Endele S, Enklaar T, Fuhry M, Zabel B. Human CLAPS2 encoding AP17, a small chain of the clathrin-associated protein complex: cDNA cloning and chromosomal assignment to 19q13.2-->q13.3. Cytogenet Cell Genet. 1996;75:132-5 pubmed
    ..The cDNA is highly conserved between rat and human. Human AP17, gene symbol CLAPS2 (clathrin-associated/assembly/adaptor protein, small 3, 17 kDa), was assigned to chromosome region 19q13.2-->q13.3. ..
  9. Martinelli D, Dionisi Vici C. AP1S1 defect causing MEDNIK syndrome: a new adaptinopathy associated with defective copper metabolism. Ann N Y Acad Sci. 2014;1314:55-63 pubmed publisher

More Information


  1. Holzmann K, Pöltl A, Sauermann G. A novel spliced transcript of human CLAPS2 encoding a protein alternative to clathrin adaptor protein AP17. Gene. 1998;220:39-44 pubmed
    ..The finding of a putative intron in a human EST cDNA clone suggests that mRNAs for AP17 and AP17Delta are formed by alternative splicing. In addition, the identity of human and rat AP17 amino acid sequences is demonstrated. ..
  2. Kirchhausen T, Nathanson K, Matsui W, Vaisberg A, Chow E, Burne C, et al. Structural and functional division into two domains of the large (100- to 115-kDa) chains of the clathrin-associated protein complex AP-2. Proc Natl Acad Sci U S A. 1989;86:2612-6 pubmed
    ..Their amino-terminal domains are relatively invariant whereas their carboxyl-terminal domains are variable in both sequence and length. We propose that the variable domains select receptors for inclusion in coated vesicles. ..
  3. Shim J, Sternberg P, Lee J. Distinct and redundant functions of mu1 medium chains of the AP-1 clathrin-associated protein complex in the nematode Caenorhabditis elegans. Mol Biol Cell. 2000;11:2743-56 pubmed
    ..Thus, apm-1 and unc-101 encode two highly related micro1 chains that share redundant and distinct functions within AP-1 clathrin-associated protein complexes of the same tissue. ..
  4. Takatsu H, Futatsumori M, Yoshino K, Yoshida Y, Shin H, Nakayama K. Similar subunit interactions contribute to assembly of clathrin adaptor complexes and COPI complex: analysis using yeast three-hybrid system. Biochem Biophys Res Commun. 2001;284:1083-9 pubmed
  5. Nesbit M, Hannan F, Howles S, Reed A, Cranston T, Thakker C, et al. Mutations in AP2S1 cause familial hypocalciuric hypercalcemia type 3. Nat Genet. 2013;45:93-7 pubmed publisher
    ..Thus, our results identify a new role for AP2 in extracellular calcium homeostasis. ..
  6. Matsui W, Kirchhausen T. Stabilization of clathrin coats by the core of the clathrin-associated protein complex AP-2. Biochemistry. 1990;29:10791-8 pubmed
    ..These results are consistent with the proposal that the AP core contains the binding site(s) for clathrin, while the alpha- and beta-chain appendages interact with membrane components of coated pits and coated vesicles...
  7. Fujisawa Y, Yamaguchi R, Satake E, Ohtaka K, Nakanishi T, Ozono K, et al. Identification of AP2S1 mutation and effects of low calcium formula in an infant with hypercalcemia and hypercalciuria. J Clin Endocrinol Metab. 2013;98:E2022-7 pubmed publisher
    ..The early infantile age of this patient would have played a certain role in the occurrence of hypercalciuria, and low calcium formula is worth attempting in infants with FHH. ..
  8. Lambert A, Grybek V, Francou B, Esterle L, Bertrand G, Bouligand J, et al. Analysis of AP2S1, a calcium-sensing receptor regulator, in familial and sporadic isolated hypoparathyroidism. J Clin Endocrinol Metab. 2014;99:E469-73 pubmed publisher
    ..None of the 60 patients presented with nucleotidic changes or copy number variation in the AP2S1 gene, thereby excluding AP2S1 defects as a frequent cause of isolated hypoparathyroidism. ..
  9. Saillour Y, Zanni G, Des Portes V, Heron D, Guibaud L, Iba Zizen M, et al. Mutations in the AP1S2 gene encoding the sigma 2 subunit of the adaptor protein 1 complex are associated with syndromic X-linked mental retardation with hydrocephalus and calcifications in basal ganglia. J Med Genet. 2007;44:739-44 pubmed
    ..It may be possible to use this feature to identify families with X-linked mental retardation that should be screened for mutations in AP1S2. ..
  10. VanRenterghem B, Morin M, Czech M, Heller Harrison R. Interaction of insulin receptor substrate-1 with the sigma3A subunit of the adaptor protein complex-3 in cultured adipocytes. J Biol Chem. 1998;273:29942-9 pubmed
    ..These results are consistent with the hypothesis that sigma3A serves as an IRS-1 receptor that may dictate the subcellular localization and the signaling functions of IRS-1. ..
  11. Phan H, Finlay J, Chu D, Tan P, Kirchhausen T, Payne G. The Saccharomyces cerevisiae APS1 gene encodes a homolog of the small subunit of the mammalian clathrin AP-1 complex: evidence for functional interaction with clathrin at the Golgi complex. EMBO J. 1994;13:1706-17 pubmed
    ..The effect of aps1 delta on cells devoid of clathrin function suggests that Aps1p also participates in clathrin-independent processes. ..
  12. Nakai M, Takada T, Endo T. Cloning of the YAP19 gene encoding a putative yeast homolog of AP19, the mammalian small chain of the clathrin-assembly proteins. Biochim Biophys Acta. 1993;1174:282-4 pubmed
    ..The identification of YAP19 supports the proposal that yeast cells also contain the Golgi-associated clathrin-assembly protein complex. ..
  13. Hogarth C, Roy A, Ebert D. Genomic evidence for the absence of a functional cholesteryl ester transfer protein gene in mice and rats. Comp Biochem Physiol B Biochem Mol Biol. 2003;135:219-29 pubmed
    ..Thus, the lack of CETP activity in both the mouse and the rat is most likely due to an evolutionary event that occurred before these species diverged and not to altered regulation of the gene or function of the gene product. ..
  14. Gokool S. Sigma 1- and mu 1-Adaptin homologues of Leishmania mexicana are required for parasite survival in the infected host. J Biol Chem. 2003;278:29400-9 pubmed
  15. Aissani B, Sinnett D. Fine physical and transcript mapping of a 1.8 Mb region spanning the locus for childhood acute lymphoblastic leukemia on chromosome 12p12. 3. Gene. 1999;240:297-305 pubmed
    ..The new map provides a molecular framework for the identification of novel genes and transcriptional units in the ALL interval. ..
  16. Takatsu H, Sakurai M, Shin H, Murakami K, Nakayama K. Identification and characterization of novel clathrin adaptor-related proteins. J Biol Chem. 1998;273:24693-700 pubmed
    ..These data suggest that gamma2-adaptin constitute a novel adaptor-related complex that participates in a transport step different from that of AP-1. ..
  17. Martinelli D, Travaglini L, Drouin C, Ceballos Picot I, Rizza T, Bertini E, et al. MEDNIK syndrome: a novel defect of copper metabolism treatable by zinc acetate therapy. Brain. 2013;136:872-81 pubmed publisher
    ..Our results may also contribute to understand the mechanism(s) of intracellular trafficking of copper pumps...
  18. Maldonado Mendoza I, Nessler C. Cloning and expression of a plant homologue of the small subunit of the Golgi-associated clathrin assembly protein AP19 from Camptotheca acuminata. Plant Mol Biol. 1996;32:1149-53 pubmed
    ..DNA blot analysis suggests that the AP19S of C. acuminata are encoded by a small gene family. CAP19 was expressed ubiquitously throughout the plant suggesting that it may be involved in general Golgi-mediated secretion. ..
  19. Page L, Robinson M. Targeting signals and subunit interactions in coated vesicle adaptor complexes. J Cell Biol. 1995;131:619-30 pubmed
    ..These results indicate that the adaptor subunits act in concert to target the complex to the appropriate membrane. ..
  20. Dell Angelica E, Ohno H, Ooi C, Rabinovich E, Roche K, Bonifacino J. AP-3: an adaptor-like protein complex with ubiquitous expression. EMBO J. 1997;16:917-28 pubmed
    ..These results suggest that the sigma3 chains are components of a novel, ubiquitous adaptor-like complex involved in the recognition of tyrosine-based sorting signals. ..
  21. Sosa R, Weber M, Wen Y, O Halloran T. A single ? adaptin contributes to AP1 and AP2 complexes and clathrin function in Dictyostelium. Traffic. 2012;13:305-16 pubmed publisher
    ..Our results support the essential contribution of a single ? subunit to the stability and function of AP1 and AP2 in a simple eukaryote. ..
  22. Liu A, Aguet F, Danuser G, Schmid S. Local clustering of transferrin receptors promotes clathrin-coated pit initiation. J Cell Biol. 2010;191:1381-93 pubmed publisher
    ..Together these results demonstrate that cargo composition is a key source of the differential dynamics of CCPs. ..
  23. Ma Y, Takeuchi M, Sugiura R, Sio S, Kuno T. Deletion mutants of AP-1 adaptin subunits display distinct phenotypes in fission yeast. Genes Cells. 2009;14:1015-28 pubmed publisher
    ..Altogether, results suggest that the four subunits are all essential for the heterotetrameric complex formation and for the AP-1 function in exit transport from endosomes. ..
  24. Montpetit A, Cote S, Brustein E, Drouin C, Lapointe L, Boudreau M, et al. Disruption of AP1S1, causing a novel neurocutaneous syndrome, perturbs development of the skin and spinal cord. PLoS Genet. 2008;4:e1000296 pubmed publisher
    ..Together, these results confirm AP1S1 as the gene responsible for MEDNIK syndrome and demonstrate a critical role of AP1S1 in development of the skin and spinal cord. ..
  25. Shim J, Lee J. The AP-3 clathrin-associated complex is essential for embryonic and larval development in Caenorhabditis elegans. Mol Cells. 2005;19:452-7 pubmed
    ..APM-3 is expressed in most cells, particularly strongly in spermatheca and vulva. We conclude that the products of the C. elegans m3, s3, b3 and d genes are essential for embryogenesis and larval development. ..
  26. Zhou J, Yang J, Zhao L, Xin Z. Variants in KCNQ1, AP3S1, MAN2A1, and ALDH7A1 and the risk of type 2 diabetes in the Chinese Northern Han population: a case-control study and meta-analysis. Med Sci Monit. 2010;16:BR179-83 pubmed
    ..05). Meta-analysis yielded an OR of 1.36 (95%CI: 1.23-1.51) for rs2237892. In this study the effects of KCNQ1 and AP3S1 variants on susceptibility to T2D in the Chinese Northern Han population were confirmed. ..
  27. Fiori L, Zouk H, Himmelman C, Turecki G. X chromosome and suicide. Mol Psychiatry. 2011;16:216-26 pubmed publisher