Plectin

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Plectin
Protein PLEC1 PDB 1mb8.png
PDB rendering based on 1mb8.
Available structures
PDB Ortholog search: PDBe, RCSB
Identifiers
Symbols PLEC ; EBS1; EBSO; HD1; LGMD2Q; PCN; PLEC1; PLEC1b; PLTN
External IDs OMIM601282 MGI1277961 HomoloGene384 ChEMBL: 1293240 GeneCards: PLEC Gene
Orthologs
Species Human Mouse
Entrez 5339 18810
Ensembl ENSG00000178209 ENSMUSG00000022565
UniProt Q15149 Q9QXS1
RefSeq (mRNA) NM_000445 NM_001163540
RefSeq (protein) NP_000436 NP_001157012
Location (UCSC) Chr 8:
144.99 – 145.05 Mb
Chr 15:
76.17 – 76.23 Mb
PubMed search [1] [2]

Plectin is a giant protein (c500 kDa) found in nearly all mammalian cells which acts as a link between the three main components of the cytoskeleton: actin microfilaments, microtubules and intermediate filaments.[1] In addition plectin links the cytoskeleton to junctions found in the plasma membrane that structurally connect different cells. By holding these different networks together plectin plays an important role in maintaining the mechanical integrity and viscoelastic properties of tissues.[2]

Structure[edit]

The structure of plectin is thought to be a dimer consisting of a central coiled coil of alpha helices connecting two large globular domains (one at each terminus). These globular domains are responsible for connecting plectin to its various cytoskeletal targets. The carboxy-terminal domain is made of 6 highly homologous repeating regions. The subdomain between regions five and six of this domain is known to connect to the intermediate filaments cytokeratin and vimentin. At the opposite end of the protein, in the N-terminal domain, a region has been defined as responsible for binding to actin. In 2004 the exact crystal structure of this actin-binding domain (ABD) was determined in mice and shown to be composed of two calponin homology (CH) domains.[3]

Function[edit]

Through the use of gold-immunoelectron microscopy, immunoblotting and immunofluorescence experiments plectin has been found to associate with all three major components of the cytoskeleton. With the use of microscopy especially plectin has been shown to directly connect microtubules to intermediate filaments as well as to each other. While plectin has been observed to mediate interactions between actin and intermediate filaments and associate with each independently, a direct linkage by plectin between these two filaments has not been completely proven. It may be that plectin actually connects to proteins associated with each rather than directly. Besides serving as a linker protein between the main elements of the cytoskeleton, plectin also forms connections between other cytoskeletally related proteins as well. Plectin has been shown to directly link Myosin II motor proteins and intermediate filaments. In in vitro assays plectin has been found to bind subplasma membrane skeleton proteins such as alpha-spectrin and fodrin. Over the past decade plectin has been identified as an important component linking the cytoskeleton to intercellular junctions which enable the structural integrity of a tissue as a whole. Two such junctions, desmosomes and hemidesmosomes which link intermediate filament networks between cells have been shown to associate with plectin. Plectin has been revealed to localize to the desmosomes and in vitro studies have shown that it can form bridges between the desmosome protein, desmoplakin and intermediate filaments. In hemidesmosomes plectin has been shown to interact with the integrin β4 subunits of the hemidesmosome plaque and function in a clamp like manner to crosslink the intermediate filament, cytokeratin to the junction.

Pancreatic Cancer[edit]

Plectin has been proposed as a biomarker for pancreatic cancer.[4][5] Although normally a cytoplasmic protein, plectin is expressed on the cell membrane in pancreatic ductal adenocarcinoma (PDAC) and can therefore be used to target PDAC cells.[4]

Interactions[edit]

Plectin has been shown to interact with SPTAN1[6][7] and Vimentin.[6][7]

See also[edit]

References[edit]

  1. ^ Svitkina TM, Verkhovsky AB, Borisy GG (1996). "Plectin sidearms mediate interaction of intermediate filaments with microtubules and other components of the cytoskeleton". J. Cell Biol. 135 (4): 991–1007. doi:10.1083/jcb.135.4.991. PMC 2133373. PMID 8922382. 
  2. ^ Wiche G (1998). "Role of plectin in cytoskeleton organization and dynamics" (abstract). J. Cell. Sci. 111 (17): 2477–86. PMID 9701547. 
  3. ^ Sevcík J, Urbániková L, Kost'an J, Janda L, Wiche G (2004). "Actin-binding domain of mouse plectin. Crystal structure and binding to vimentin". Eur. J. Biochem. 271 (10): 1873–84. doi:10.1111/j.1432-1033.2004.04095.x. PMID 15128297. 
  4. ^ a b Kelly KA, Bardeesy N, Anbazhagan R, Gurumurthy S, Berger J, Alencar H, Depinho RA, Mahmood U, Weissleder R (April 2008). "Targeted nanoparticles for imaging incipient pancreatic ductal adenocarcinoma". PLoS Med. 5 (4): e85. doi:10.1371/journal.pmed.0050085. PMC 2292750. PMID 18416599. 
  5. ^ Bausch D, Thomas S, Mino-Kenudson M, Fernández-del CC, Bauer TW, Williams M, Warshaw AL, Thayer SP, Kelly KA (January 2011). "Plectin-1 as a novel biomarker for pancreatic cancer". Clin. Cancer Res. 17 (2): 302–9. doi:10.1158/1078-0432.CCR-10-0999. PMC 3044444. PMID 21098698. 
  6. ^ a b Herrmann H, Wiche G (January 1987). "Plectin and IFAP-300K are homologous proteins binding to microtubule-associated proteins 1 and 2 and to the 240-kilodalton subunit of spectrin". J. Biol. Chem. 262 (3): 1320–5. PMID 3027087. 
  7. ^ a b Brown MJ, Hallam JA, Liu Y, Yamada KM, Shaw S (July 2001). "Cutting edge: integration of human T lymphocyte cytoskeleton by the cytolinker plectin". J. Immunol. 167 (2): 641–5. doi:10.4049/jimmunol.167.2.641. PMID 11441066. 

Further reading[edit]

External links[edit]