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Gene Review

HPCA  -  hippocalcin

Homo sapiens

Synonyms: BDR2, Calcium-binding protein BDR-2, Neuron-specific calcium-binding protein hippocalcin
 
 
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Disease relevance of HPCA

  • Here we report that NAIP, through its third baculovirus inhibitory repeat domain (BIR3), binds the neuron-restricted calcium-binding protein, hippocalcin, in an interaction promoted by calcium [1].
  • This phenotypic difference is also helpful in distinguishing hyperplastic Hurthle cell proliferation in Hashimoto's thyroiditis from HPCA or WLPCA [2].
  • Using follow-up imaging, the correlation of the hyperdense PCA (HPCA) with infarct size, thalamic infarction, and bleeding were investigated [3].
  • The Hurthle cell (HPCA) and Warthin-like (WLPCA) variants of papillary carcinoma are two closely related entities that arise in association with Hashimoto's thyroiditis and share the presence of oxyphilic changes in the lining of epithelial cells and the presence of papillary nuclear features [2].
  • CONCLUSIONS: An HPCA was detected in more than one third of all patients with PCA ischemia, suiting the incidence of the hyperdense MCA [3].
 

High impact information on HPCA

  • Translocation of hippocalcin in response to increased cytosolic [Ca2+] was examined in HeLa cells expressing hippocalcin-enhanced yellow fluorescent protein (EYFP) to determine the dynamics and Ca2+ affinity of the Ca2+/myristoyl switch in living cells [4].
  • Hippocalcin is a neuronal calcium sensor protein that possesses a Ca2+/myristoyl switch allowing it to translocate to membranes [4].
  • NAIP interacts with hippocalcin and protects neurons against calcium-induced cell death through caspase-3-dependent and -independent pathways [1].
  • Thus NAIP, in conjunction with hippocalcin, can protect neurons against calcium-induced cell death in caspase-3-activated and non-activated pathways [1].
  • Over-expression of the BIR3 domain or hippocalcin alone did not substantially enhance cell survival, but co-expression greatly increased their protective effects [1].
 

Chemical compound and disease context of HPCA

 

Biological context of HPCA

  • Dual imaging of hippocalcin-EYFP and cytosolic Ca(2+) concentration in Fura Red-loaded cells demonstrated the kinetics of the Ca(2+)/myristoyl switch in living cells and showed that hippocalcin rapidly translocated with a half-time of approximately 12 s after a short lag period when Ca(2+) was elevated [5].
  • A cDNA clone (hHLP2) encoding a novel calcium-binding protein structurally related to hippocalcin has been isolated from the human hippocampus cDNA library [6].
  • Fluorescence in-situ hybridization revealed that the human hippocalcin gene is located at chromosome 1 p34.2-35 and the mouse hippocalcin gene at chromosome 4 D2-D3 [7].
  • The human and mouse hippocalcin genes contain three exons and two introns, and span approximately 7 and 8kb, respectively [7].
  • In contrast, when either PCA or HPCA is added to a preformed Er.NO complex, no substrate binding to the Fe2+ is detected [8].
 

Anatomical context of HPCA

  • The human hippocalcin gene was mapped to chromosome 1 by amplification of human hippocalcin-specific DNA fragment on DNA from human-rodent somatic cell hybrids by using the polymerase chain reaction [9].
  • In the case of hippocalcin and NCS-1, or alternatively KChIP1 (K+ channel-interacting protein 1), their N-terminal myristoylation motifs are sufficient for targeting to distinct organelles [10].
  • All cases of HPCA and WLPCA of the thyroid showed reactivity in 50% or more of the nuclei in the neoplastic cell population [2].
  • The thalamus was affected significantly more often (P=0.009) and the size of the infarct was significantly more often large than medium (P=0.018) or small (P<0.001) when an HPCA was present [3].
  • The membrane localisation of each NCS protein required myristoylation and minimal myristoylation motifs of hippocalcin or KChIP1 were sufficient to target fusion proteins to either TGN/plasma membrane or to punctate structures [11].
 

Associations of HPCA with chemical compounds

  • High-affinity interaction of the N-terminal myristoylation motif of the neuronal calcium sensor protein hippocalcin with phosphatidylinositol 4,5-bisphosphate [10].
  • The substrate (2,3-dihydroxyphenylacetate [HPCA]) chelates the metal asymmetrically at sites trans to the two imidazole ligands and interacts with a unique, mobile C-terminal loop [12].
  • Second-sphere active-site residues that are positioned to interact with the HPCA and/or bound O2 during catalysis are identified and discussed in the context of current mechanistic hypotheses [12].
  • Additionally, the [Ca(2+)] dependency of the calcium-induced translocation of hippocalcin is investigated [13].
  • Hippocalcin, a recently identified Ca(2+)-binding protein of the recoverin family exclusively expressed in the hippocampus, has a primary structure containing three putative Ca(2+)-binding sites (EF-hands) and a possible NH2-terminal myristoylation site [14].
 

Regulatory relationships of HPCA

 

Other interactions of HPCA

  • Upon the elevation of intracellular Ca(2+), hippocalcin rapidly translocated to the same perinuclear compartment as NCS-1 [5].
  • Permeabilization of transfected cells using digitonin caused loss of hippocalcin and neurocalcin delta in the absence of calcium, but in the presence of 10 microm Ca(2+), both proteins translocated to and were retained in the perinuclear region [5].
  • In conclusion, HPCA and WLPCA are Rb-positive and E2F-1-positive; PCA and FVPCA are Rb-negative and E2F1-negative [2].
  • DN-PLD2 suppressed increase of basal PLD activity in hippocalcin transfected cells, suggesting that increased basal PLD activity is due to PLD2 over-expression [15].
  • Here, we proposed that hippocalcin was involved in extracellular signal-regulated kinase (ERK)-mediated PLD2 expression [15].
 

Analytical, diagnostic and therapeutic context of HPCA

  • Molecular cloning of a novel calcium-binding protein structurally related to hippocalcin from human brain and chromosomal mapping of its gene [6].
  • Southern blot analysis of the human and mouse genomic DNAs demonstrated that the positive bands coincide exactly with those expected from the sequence of the cloned genes, indicating that the human and mouse hippocalcin genes are present as a single-copy gene [7].
  • Children in Group 1 (HPCA/LBI) used significantly less morphine during their hospitalization, were hospitalized fewer days, and reported lower pain scores on day 2 [16].
  • We have previously isolated a 22 kDa protein from a rat brain which was found to be involved in activating phospholipsae D (PLD), and identified the protein as hippocalcin through sequence analysis [15].

References

  1. NAIP interacts with hippocalcin and protects neurons against calcium-induced cell death through caspase-3-dependent and -independent pathways. Mercer, E.A., Korhonen, L., Skoglösa, Y., Olsson, P.A., Kukkonen, J.P., Lindholm, D. EMBO J. (2000) [Pubmed]
  2. The phenotype of Hurthle and Warthin-like papillary thyroid carcinomas is distinct from classic papillary carcinoma as to the expression of retinoblastoma protein and E2F-1 transcription factor. Anwar, F. Appl. Immunohistochem. Mol. Morphol. (2003) [Pubmed]
  3. The hyperdense posterior cerebral artery sign: a computed tomography marker of acute ischemia in the posterior cerebral artery territory. Krings, T., Noelchen, D., Mull, M., Willmes, K., Meister, I.G., Reinacher, P., Toepper, R., Thron, A.K. Stroke (2006) [Pubmed]
  4. Dynamics and calcium sensitivity of the Ca2+/myristoyl switch protein hippocalcin in living cells. O'Callaghan, D.W., Tepikin, A.V., Burgoyne, R.D. J. Cell Biol. (2003) [Pubmed]
  5. Differential use of myristoyl groups on neuronal calcium sensor proteins as a determinant of spatio-temporal aspects of Ca2+ signal transduction. O'Callaghan, D.W., Ivings, L., Weiss, J.L., Ashby, M.C., Tepikin, A.V., Burgoyne, R.D. J. Biol. Chem. (2002) [Pubmed]
  6. Molecular cloning of a novel calcium-binding protein structurally related to hippocalcin from human brain and chromosomal mapping of its gene. Kobayashi, M., Takamatsu, K., Fujishiro, M., Saitoh, S., Noguchi, T. Biochim. Biophys. Acta (1994) [Pubmed]
  7. Genomic structure and chromosomal mapping of the human and mouse hippocalcin genes. Masaki, T., Sakai, E., Furuta, Y., Kobayashi, M., Takamatsu, K. Gene (1998) [Pubmed]
  8. Simultaneous binding of nitric oxide and isotopically labeled substrates or inhibitors by reduced protocatechuate 3,4-dioxygenase. Orville, A.M., Lipscomb, J.D. J. Biol. Chem. (1993) [Pubmed]
  9. Molecular cloning of human hippocalcin cDNA and chromosomal mapping of its gene. Takamatsu, K., Kobayashi, M., Saitoh, S., Fujishiro, M., Noguchi, T. Biochem. Biophys. Res. Commun. (1994) [Pubmed]
  10. High-affinity interaction of the N-terminal myristoylation motif of the neuronal calcium sensor protein hippocalcin with phosphatidylinositol 4,5-bisphosphate. O'Callaghan, D.W., Haynes, L.P., Burgoyne, R.D. Biochem. J. (2005) [Pubmed]
  11. Residues within the myristoylation motif determine intracellular targeting of the neuronal Ca2+ sensor protein KChIP1 to post-ER transport vesicles and traffic of Kv4 K+ channels. O'Callaghan, D.W., Hasdemir, B., Leighton, M., Burgoyne, R.D. J. Cell. Sci. (2003) [Pubmed]
  12. Crystallographic comparison of manganese- and iron-dependent homoprotocatechuate 2,3-dioxygenases. Vetting, M.W., Wackett, L.P., Que, L., Lipscomb, J.D., Ohlendorf, D.H. J. Bacteriol. (2004) [Pubmed]
  13. Role of myristoylation in the intracellular targeting of neuronal calcium sensor (NCS) proteins. O'Callaghan, D.W., Burgoyne, R.D. Biochem. Soc. Trans. (2003) [Pubmed]
  14. Myristoylation of hippocalcin is linked to its calcium-dependent membrane association properties. Kobayashi, M., Takamatsu, K., Saitoh, S., Noguchi, T. J. Biol. Chem. (1993) [Pubmed]
  15. Hippocalcin increases phospholipase D2 expression through extracellular signal-regulated kinase activation and lysophosphatidic acid potentiates the hippocalcin-induced phospholipase D2 expression. Oh, D.Y., Yon, C., Oh, K.J., Lee, K.S., Han, J.S. J. Cell. Biochem. (2006) [Pubmed]
  16. A comparison of two regimens of patient-controlled analgesia for children with sickle cell disease. Trentadue, N.O., Kachoyeanos, M.K., Lea, G. Journal of pediatric nursing. (1998) [Pubmed]
 
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