SYNPO2

Myopodin protein, also called Synaptopodin-2 is a protein that in humans is encoded by the SYNPO2 gene.[5][6][7] Myopodin is expressed in cardiac, smooth muscle and skeletal muscle, and localizes to Z-disc structures.

SYNPO2
Identifiers
AliasesSYNPO2, synaptopodin 2, SYISL
External IDsMGI: 2153070 HomoloGene: 15400 GeneCards: SYNPO2
Orthologs
SpeciesHumanMouse
Entrez

171024

118449

Ensembl

ENSG00000172403

ENSMUSG00000050315

UniProt

Q9UMS6

Q91YE8

RefSeq (mRNA)

NM_080451
NM_001388502
NM_001389265
NM_001389266

RefSeq (protein)

NP_001122405
NP_001122406
NP_001273683
NP_001273684
NP_597734

NP_536699
NP_001375431
NP_001376194
NP_001376195

Location (UCSC)Chr 4: 118.85 – 119.06 MbChr 3: 122.87 – 123.03 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

Structure

Myopodin is a 117.4 kDa protein composed of 1093 amino acids,[8] although four alternatively-spliced isoforms have been described.[9] Myopodin contains one PPXY motif, multiple PXXP motifs, and two potential nuclear localization sequences (one N-terminal and one C-terminal).[5] 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.[5]

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.[5] 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.[5] The nuclear localization of myopodin is sensitive to Importin 13, which directly binds myopodin and facilitates its translocation.[6] Importin binding and nuclear import of myopodin appears to be mediated by serine/threonine phosphorylation-dependent binding of myopodin to 14-3-3 beta[10] 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.[11] 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.[11]

Interactions

Myopodin interacts with:

References

  1. GRCh38: Ensembl release 89: ENSG00000172403 - Ensembl, May 2017
  2. GRCm38: Ensembl release 89: ENSMUSG00000050315 - Ensembl, May 2017
  3. "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. Weins A, Schwarz K, Faul C, Barisoni L, Linke WA, Mundel P (Oct 2001). "Differentiation- and stress-dependent nuclear cytoplasmic redistribution of myopodin, a novel actin-bundling protein". The Journal of Cell Biology. 155 (3): 393–404. doi:10.1083/jcb.200012039. PMC 2150840. PMID 11673475.
  6. Liang J, Ke G, You W, Peng Z, Lan J, Kalesse M, Tartakoff AM, Kaplan F, Tao T (Jan 2008). "Interaction between importin 13 and myopodin suggests a nuclear import pathway for myopodin". Molecular and Cellular Biochemistry. 307 (1–2): 93–100. doi:10.1007/s11010-007-9588-1. PMID 17828378. S2CID 19273082.
  7. "Entrez Gene: SYNPO2 synaptopodin 2".
  8. Joon-Sub Chung. "Cardiac Organellar Protein Atlas Knowledgebase (COPaKB) —— Protein Information". heartproteome.org.
  9. "SYNPO2 - Synaptopodin-2 - Homo sapiens (Human) - SYNPO2 gene & protein". uniprot.org.
  10. Faul C, Hüttelmaier S, Oh J, Hachet V, Singer RH, Mundel P (May 2005). "Promotion of importin alpha-mediated nuclear import by the phosphorylation-dependent binding of cargo protein to 14-3-3". The Journal of Cell Biology. 169 (3): 415–24. doi:10.1083/jcb.200411169. PMC 2171942. PMID 15883195.
  11. Faul C, Dhume A, Schecter AD, Mundel P (Dec 2007). "Protein kinase A, Ca2+/calmodulin-dependent kinase II, and calcineurin regulate the intracellular trafficking of myopodin between the Z-disc and the nucleus of cardiac myocytes". Molecular and Cellular Biology. 27 (23): 8215–27. doi:10.1128/MCB.00950-07. PMC 2169179. PMID 17923693.

Further reading


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