| Structural highlights
Function
[SOCS2_HUMAN] SOCS family proteins form part of a classical negative feedback system that regulates cytokine signal transduction. SOCS2 appears to be a negative regulator in the growth hormone/IGF1 signaling pathway. Probable substrate recognition component of a SCF-like ECS (Elongin BC-CUL2/5-SOCS-box protein) E3 ubiquitin-protein ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of target proteins. [ELOC_HUMAN] SIII, also known as elongin, is a general transcription elongation factor that increases the RNA polymerase II transcription elongation past template-encoded arresting sites. Subunit A is transcriptionally active and its transcription activity is strongly enhanced by binding to the dimeric complex of the SIII regulatory subunits B and C (elongin BC complex).[1] The elongin BC complex seems to be involved as an adapter protein in the proteasomal degradation of target proteins via different E3 ubiquitin ligase complexes, including the von Hippel-Lindau ubiquitination complex CBC(VHL). By binding to BC-box motifs it seems to link target recruitment subunits, like VHL and members of the SOCS box family, to Cullin/RBX1 modules that activate E2 ubiquitination enzymes.[2] [ELOB_HUMAN] SIII, also known as elongin, is a general transcription elongation factor that increases the RNA polymerase II transcription elongation past template-encoded arresting sites. Subunit A is transcriptionally active and its transcription activity is strongly enhanced by binding to the dimeric complex of the SIII regulatory subunits B and C (elongin BC complex).[3] [4] The elongin BC complex seems to be involved as an adapter protein in the proteasomal degradation of target proteins via different E3 ubiquitin ligase complexes, including the von Hippel-Lindau ubiquitination complex CBC(VHL). By binding to BC-box motifs it seems to link target recruitment subunits, like VHL and members of the SOCS box family, to Cullin/RBX1 modules that activate E2 ubiquitination enzymes.[5] [6]
Publication Abstract from PubMed
Suppressor of cytokine signalling 2 (SOCS2) is the substrate-binding component of a Cullin-RING E3 ubiquitin ligase (CRL) complex that targets phosphorylated hormone receptors for degradation by the ubiquitin-proteasome system. As a key regulator of the transcriptional response to growth signals, SOCS2 and its protein complex partners are potential targets for small molecule development. We found that crystals of SOCS2 in complex with its adaptor proteins, Elongin C and Elongin B, underwent a change in crystallographic parameters when treated with dimethyl sulfoxide during soaking experiments. To solve the phase problem for the new crystal form we identified the presence of arsenic atoms in the crystals, a result of covalent modification of cysteines by cacodylate, and successfully extracted anomalous signal from these atoms for experimental phasing. The resulting structure provides a means for solving future structures where the crystals must be treated with DMSO for ligand soaking approaches. Additionally, the conformational changes induced in this structure reveal flexibility within SOCS2 that match those postulated by previous molecular dynamics simulations. This conformational flexibility illustrates how SOCS2 can orient its substrates for successful ubiquitination by other elements of the CRL complex.
Serendipitous SAD Solution for DMSO-Soaked SOCS2-ElonginC-ElonginB Crystals Using Covalently Incorporated Dimethylarsenic: Insights into Substrate Receptor Conformational Flexibility in Cullin RING Ligases.,Gadd MS, Bulatov E, Ciulli A PLoS One. 2015 Jun 29;10(6):e0131218. doi: 10.1371/journal.pone.0131218., eCollection 2015. PMID:26121586[7]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Kario E, Marmor MD, Adamsky K, Citri A, Amit I, Amariglio N, Rechavi G, Yarden Y. Suppressors of cytokine signaling 4 and 5 regulate epidermal growth factor receptor signaling. J Biol Chem. 2005 Feb 25;280(8):7038-48. Epub 2004 Dec 7. PMID:15590694 doi:10.1074/jbc.M408575200
- ↑ Kario E, Marmor MD, Adamsky K, Citri A, Amit I, Amariglio N, Rechavi G, Yarden Y. Suppressors of cytokine signaling 4 and 5 regulate epidermal growth factor receptor signaling. J Biol Chem. 2005 Feb 25;280(8):7038-48. Epub 2004 Dec 7. PMID:15590694 doi:10.1074/jbc.M408575200
- ↑ Garrett KP, Aso T, Bradsher JN, Foundling SI, Lane WS, Conaway RC, Conaway JW. Positive regulation of general transcription factor SIII by a tailed ubiquitin homolog. Proc Natl Acad Sci U S A. 1995 Aug 1;92(16):7172-6. PMID:7638163
- ↑ Kario E, Marmor MD, Adamsky K, Citri A, Amit I, Amariglio N, Rechavi G, Yarden Y. Suppressors of cytokine signaling 4 and 5 regulate epidermal growth factor receptor signaling. J Biol Chem. 2005 Feb 25;280(8):7038-48. Epub 2004 Dec 7. PMID:15590694 doi:10.1074/jbc.M408575200
- ↑ Garrett KP, Aso T, Bradsher JN, Foundling SI, Lane WS, Conaway RC, Conaway JW. Positive regulation of general transcription factor SIII by a tailed ubiquitin homolog. Proc Natl Acad Sci U S A. 1995 Aug 1;92(16):7172-6. PMID:7638163
- ↑ Kario E, Marmor MD, Adamsky K, Citri A, Amit I, Amariglio N, Rechavi G, Yarden Y. Suppressors of cytokine signaling 4 and 5 regulate epidermal growth factor receptor signaling. J Biol Chem. 2005 Feb 25;280(8):7038-48. Epub 2004 Dec 7. PMID:15590694 doi:10.1074/jbc.M408575200
- ↑ Gadd MS, Bulatov E, Ciulli A. Serendipitous SAD Solution for DMSO-Soaked SOCS2-ElonginC-ElonginB Crystals Using Covalently Incorporated Dimethylarsenic: Insights into Substrate Receptor Conformational Flexibility in Cullin RING Ligases. PLoS One. 2015 Jun 29;10(6):e0131218. doi: 10.1371/journal.pone.0131218., eCollection 2015. PMID:26121586 doi:http://dx.doi.org/10.1371/journal.pone.0131218
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