SYNPO2

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Identifiers
Aliases
External IDs	GeneCards: [1]
Orthologs
Species	Human	Mouse
Entrez	n/a	n/a
Ensembl	n/a	n/a
UniProt	n/a	n/a
RefSeq (mRNA)	n/a	n/a
RefSeq (protein)	n/a	n/a
Location (UCSC)	n/a	n/a
PubMed search	n/a	n/a
Wikidata
View/Edit Human

Myopodin protein, also called Synaptopodin-2 is a protein that in humans is encoded by the SYNPO2 gene. Myopodin is expressed in cardiac, smooth muscle and skeletal muscle, and localizes to Z-disc structures.

Structure

Myopodin is a 117.4 kDa protein composed of 1093 amino acids, although four alternatively-spliced isoforms have been described. Myopodin contains one PPXY motif, multiple PXXP motifs, and two potential nuclear localization sequences (one N-terminal and one C-terminal). PPXY motifs have been shown to mediate interactions, and PXXP motifs represent potential sites of interaction for SH3 domain-containing proteins. Myopodin contains a novel actin binding site (between amino acids 410 and 563) in the center of the protein.

Function

During myotube differentiation, myopodin interacts with stress fibers prior to co-localizing with alpha actinin-2 at Z-discs in mature striated muscle cells. Myopodin has been shown to shuttle between the nucleus and cytoplasm in myoblasts and myotubes in response to stress; its export from the nucleus is sensitive to lemtomycin B. The nuclear localization of myopodin is sensitive to Importin 13, which directly binds myopodin and facilitates its translocation. Importin binding and nuclear import of myopodin appears to be mediated by serine/threonine phosphorylation-dependent binding of myopodin to 14-3-3 beta Myopodin appears to regulate compartmentalized, intracellular signal transduction between the Z-disc and nucleus in cardiac muscle cells, by forming a Z-disc signaling complex with alpha actinin-2, calcineurin, CaMKII, muscle-specific A-kinase anchoring protein, and myomegalin. Specifically, phosphorylation by protein kinase A or CaMKII, and dephosphorylation by calcineurin facilitates the binding or release, respectively, of 14-3-3-beta, and the corresponding nuclear or cytoplasmic localization, respectively, of myopodin.

Interactions

Myopodin interacts with:

• 14-3-3 beta,
• Actin, alpha, cardiac muscle 1,
• Actinin, alpha 2,
• Calcineurin,
• CaMKII,
• Importin 13, and
• Protein kinase A.

Further reading

• Houlgatte R, Mariage-Samson R, Duprat S, Tessier A, Bentolila S, Lamy B, Auffray C (Oct 1995). "The Genexpress Index: a resource for gene discovery and the genic map of the human genome". Genome Research. 5 (3): 272–304. doi:10.1101/gr.5.3.272. PMID 8593614.
• Hartley JL, Temple GF, Brasch MA (Nov 2000). "DNA cloning using in vitro site-specific recombination". Genome Research. 10 (11): 1788–95. doi:10.1101/gr.143000. PMC 310948. PMID 11076863.
• Wiemann S, Weil B, Wellenreuther R, Gassenhuber J, Glassl S, Ansorge W, Böcher M, Blöcker H, Bauersachs S, Blum H, Lauber J, Düsterhöft A, Beyer A, Köhrer K, Strack N, Mewes HW, Ottenwälder B, Obermaier B, Tampe J, Heubner D, Wambutt R, Korn B, Klein M, Poustka A (Mar 2001). "Toward a catalog of human genes and proteins: sequencing and analysis of 500 novel complete protein coding human cDNAs". Genome Research. 11 (3): 422–35. doi:10.1101/gr.GR1547R. PMC 311072. PMID 11230166.
• Simpson JC, Wellenreuther R, Poustka A, Pepperkok R, Wiemann S (Sep 2000). "Systematic subcellular localization of novel proteins identified by large-scale cDNA sequencing". EMBO Reports. 1 (3): 287–92. doi:10.1093/embo-reports/kvd058. PMC 1083732. PMID 11256614.
• Van Impe K, De Corte V, Eichinger L, Bruyneel E, Mareel M, Vandekerckhove J, Gettemans J (May 2003). "The Nucleo-cytoplasmic actin-binding protein CapG lacks a nuclear export sequence present in structurally related proteins". The Journal of Biological Chemistry. 278 (20): 17945–52. doi:10.1074/jbc.M209946200. PMID 12637565.
• Sanchez-Carbayo M, Schwarz K, Charytonowicz E, Cordon-Cardo C, Mundel P (Aug 2003). "Tumor suppressor role for myopodin in bladder cancer: loss of nuclear expression of myopodin is cell-cycle dependent and predicts clinical outcome". Oncogene. 22 (34): 5298–305. doi:10.1038/sj.onc.1206616. PMID 12917631.
• Jing L, Liu L, Yu YP, Dhir R, Acquafondada M, Landsittel D, Cieply K, Wells A, Luo JH (May 2004). "Expression of myopodin induces suppression of tumor growth and metastasis". The American Journal of Pathology. 164 (5): 1799–806. doi:10.1016/S0002-9440(10)63738-8. PMC 1615646. PMID 15111326.
• Wiemann S, Arlt D, Huber W, Wellenreuther R, Schleeger S, Mehrle A, Bechtel S, Sauermann M, Korf U, Pepperkok R, Sültmann H, Poustka A (Oct 2004). "From ORFeome to biology: a functional genomics pipeline". Genome Research. 14 (10B): 2136–44. doi:10.1101/gr.2576704. PMC 528930. PMID 15489336.
• Mehrle A, Rosenfelder H, Schupp I, del Val C, Arlt D, Hahne F, Bechtel S, Simpson J, Hofmann O, Hide W, Glatting KH, Huber W, Pepperkok R, Poustka A, Wiemann S (Jan 2006). "The LIFEdb database in 2006". Nucleic Acids Research. 34 (Database issue): D415–8. doi:10.1093/nar/gkj139. PMC 1347501. PMID 16381901.