Nucleoplasmin: Difference between revisions
Tomer Gelman (talk | contribs) No edit summary |
Michal Harel (talk | contribs) No edit summary |
||
| (One intermediate revision by one other user not shown) | |||
| Line 50: | Line 50: | ||
= Activation by Phosphorylation = | |||
NP decondensate the chromatin by the poly-glu tail, Phosphorylation on the core domain is also required for efficient decondensation. Partial phosphorylation can give the protein the ability to bind core histones, but only hyperphosphorylation of specific regions of both protein domains can make the decondensation process to begin. The hyperphosphorylation is correlated with an enhanced H2A/H2B dimer exchange activity during the decondensation of sperm chromatin. | NP decondensate the chromatin by the poly-glu tail, Phosphorylation on the core domain is also required for efficient decondensation. Partial phosphorylation can give the protein the ability to bind core histones, but only hyperphosphorylation of specific regions of both protein domains can make the decondensation process to begin. The hyperphosphorylation is correlated with an enhanced H2A/H2B dimer exchange activity during the decondensation of sperm chromatin. | ||
= orthologey in Homo sapiens = | = orthologey in Homo sapiens = | ||
the NP in Humans is made out of <scene name='46/467273/Dimer/1'>dimer</scene> while each <scene name='46/467273/Monomer/2'>monomer</scene> consisted of five chains. The structure remain similiar to the one in Xenopus but with a change in amino acids in its <scene name='46/467273/Core_domain/2'>core domain</scene>, Val insted of Ile. | the NP in Humans is made out of <scene name='46/467273/Dimer/1'>dimer</scene> while each <scene name='46/467273/Monomer/2'>monomer</scene> consisted of five chains. The structure remain similiar to the one in Xenopus but with a change in amino acids in its <scene name='46/467273/Core_domain/2'>core domain</scene>, Val insted of Ile. | ||
The Decamer bind H2A-H2B dimers and H3-H4 tetramers simultaneously, In the absence of histone tetramers the pentamer binds H2A-H2B and formes central hub. When H3-H4 tetramers are recruited this results in a functional dimerization of the complex, and the decamer being formed. | The Decamer bind H2A-H2B dimers and H3-H4 tetramers simultaneously, In the absence of histone tetramers the pentamer binds H2A-H2B and formes central hub. When H3-H4 tetramers are recruited this results in a functional dimerization of the complex, and the decamer being formed. | ||
The interaction between NP and H2A-H2B has a strong electrostatic component and the complex formation results in charge neutralization, which in turn stabilize it by diminishing the repulsion due to the proposed accumulation of negatively charged residues at the face of the NP pentamer. | |||
[[Image:Histone Storage and Nucleosome Assembly.jpg|thumb|Histone Storage and Nucleosome Assembly]] | [[Image:Histone Storage and Nucleosome Assembly.jpg|thumb|Histone Storage and Nucleosome Assembly]] | ||
| Line 90: | Line 91: | ||
= | = conservation = | ||
The loop in the core domain of Xenopus NP is not highly conserved, [[Image:1k5j.png | thumb | Xenopus]] | The loop in the core domain of Xenopus NP is not highly conserved, [[Image:1k5j.png | thumb | Xenopus]] | ||
while the core domain in human is more conserved compared to Xenopus. [[Image:3T30.png | thumb | Human]] | while the core domain in human is more conserved compared to Xenopus. [[Image:3T30.png | thumb | Human]] | ||
| Line 114: | Line 115: | ||
=3D structures of nucleoplasmin= | |||
[[1k5j]] – XlNpl core – ''Xenopus laevis'' | [[1k5j]] – XlNpl core – ''Xenopus laevis'' | ||
| Line 125: | Line 126: | ||
[[3t30]] - Human nucleoplasmin | [[3t30]] - Human nucleoplasmin | ||
= References = | |||
<references/> | <references/> | ||
2. Taneva SG1, Muñoz IG, Franco G, Falces J, Arregi I, Muga A, Montoya G, Urbaneja MA, Bañuelos S. Activation of nucleoplasmin, an oligomeric histone chaperone, challenges its stability.Biochemistry. 2008 Dec 30;47(52):13897-906. PMID:19055325 DOI:10.1021/bi800975r | 2. Taneva SG1, Muñoz IG, Franco G, Falces J, Arregi I, Muga A, Montoya G, Urbaneja MA, Bañuelos S. Activation of nucleoplasmin, an oligomeric histone chaperone, challenges its stability.Biochemistry. 2008 Dec 30;47(52):13897-906. PMID:19055325 DOI:10.1021/bi800975r | ||
| Line 142: | Line 143: | ||
7. Shuchismita Dutta, Ildiko´ V. Akey,Colin Dingwall, Kari L. Hartman,Tom Laue, Robert T. Nolte,James F. Head, and Christopher W. Akey. The Crystal Structure of Nucleoplasmin-Core: | 7. Shuchismita Dutta, Ildiko´ V. Akey,Colin Dingwall, Kari L. Hartman,Tom Laue, Robert T. Nolte,James F. Head, and Christopher W. Akey. The Crystal Structure of Nucleoplasmin-Core: | ||
Implications for Histone Binding and Nucleosome Assembly. Molecular Cell, Vol. 8, 841–853, October, 2001 | Implications for Histone Binding and Nucleosome Assembly. Molecular Cell, Vol. 8, 841–853, October, 2001 | ||
8. Isbaal Ramos, Jaime Martín-Benito, Ron Finn, Laura Bretan˜, Kerman Aloria, Jesu´ s M. Arizmendi, Juan Ausio´, Arturo Muga, Jose´ M. Valpuesta, and Adelina Prado. Nucleoplasmin Binds Histone H2A-H2B Dimers through Its Distal Face. THE JOURNAL OF BIOLOGICAL CHEMISTRY VOL. 285, NO. 44, pp. 33771–33778, October 29, 2010 | |||