Talin protein
| talin 1
| |
| Identifiers | |
| Symbol | TLN1 |
| Alt. Symbols | TLN |
| Entrez | 7094 |
| HUGO | 11845 |
| OMIM | 186745 |
| RefSeq | NM_006289 |
| UniProt | Q9Y490 |
| Other data | |
| Locus | Chr. 9 p23-p21 |
| talin 2
| |
| Identifiers | |
| Symbol | TLN2 |
| Entrez | 83660 |
| HUGO | 15447 |
| OMIM | 607349 |
| RefSeq | NM_015059 |
| UniProt | Q9Y4G6 |
| Other data | |
| Locus | Chr. 15 q15-q21 |
TALIN is a high-molecular-weight cytoskeletal protein concentrated at regions of cell–substratum contact[1] and, in lymphocytes, at cell–cell contacts[2][3]. Integrin receptors are involved in the attachment of adherent cells to extracellular matrices[4][5] and of lymphocytes to other cells. In these situations, talin codistributes with concentrations of integrins in the cell surface membrane [6][7]. Furthermore, in vitro binding studies suggest that integrins bind to talin, although with low affinity[8]. Talin also binds with high affinity to vinculin[9], another cytoskeletal protein concentrated at points of cell adhesion[10]. Finally, talin is a substrate for the Ca2+-activated protease, calpain II[11], which is also concentrated at points of cell-substratum contact[12].
Talin Domains
Talin consists of a large C-terminal rod domain that contains bundles of α-alpha helices and an N-terminal FERM (band 4.1, ezrin, radixin, and moesin) domain with three subdomains: F1, F2, and F3[13][14][15][16]. The F3 subdomain of the FERM domain contains the highest affinity integrin-binding site for integrin β tails and is sufficient to activate integrins[17].
Talin Activates Integrin αIIbβ3
A structure-function analysis reported recently[18] provides a cogent structural model (see top right) to explain talin-dependent integrin activation in three steps:
- ♦ (A) The talin F3 domain (surface representation; colored by charge), freed from its autoinhibitory interactions in the full-length protein, becomes available for binding to the integrin.
- ♦ (B) F3 engages the membrane-distal part of the β3-integrin tail (in red), which becomes ordered, but the α-β integrin interactions that hold the integrin in the low-affinity conformation remain intact.
- ♦ (C) In a subsequent step, F3 engages the membrane-proximal portion of the β3 tail while maintaining its membrane-distal interactions.
References
- ↑ Burridge, K. & Connell, L. J. Cell Biol. 97, 359−367 (1983)
- ↑ Kupfer, A., Singer, S. J. & Dennert, G. J. exp. Med. 163, 489−498 (1986)
- ↑ Burn, P., Kupfer, A. & Singer, S. J. Proc. natn. Acad. Sci. U.S.A. 85, 497−501 (1988)
- ↑ Hynes, R. O. Cell 48, 549−554 (1987)
- ↑ Ruoslahti, E. & Pierschbacher, M. D. Science 238, 491−497 (1987)
- ↑ Chen, W, T., Hasegawa, T., Hasegawa, C., Weinstock, C. & Yamada, K. M. J. Cell Biol. 100, 1103−1114 (1985)
- ↑ Kupfer, A. & Singer, S. J. J. exp. Med. 170, 1697−1713 (1989)
- ↑ Horwitz, A., Duggan, E., Buck, C., Beckerle, M. C. & Burridge, K. Nature 320, 531−533 (1986)
- ↑ Burridge, K. & Mangeat, P. Nature 308, 744−746 (1984)
- ↑ Geiger, B. Cell 18, 193−205 (1979)
- ↑ Fox, J. E. B., Goll, D. E., Reynolds, C. C. & Phillips, D. R. J. biol. Chem. 260, 1060−1066 (1985
- ↑ Beckerle, M. C., Burridge, K., DeMartino, G. N. & Croall, D. E. Cell 51, 569−577 (1987)
- ↑ Chishti A.H. et al., Trends Biochem. Sci. 23 (1998), pp. 281–282
- ↑ Garcia-Alvarez B. et al., Mol. Cell 11 (2003), pp. 49–58.
- ↑ Papagrigoriou E. et al., EMBO J. 23 (2004), pp. 2942–2951
- ↑ Rees D.J. et al., Nature 347 (1990), pp. 685–689.
- ↑ Calderwood D.A. et al., 2002 J. Biol. Chem. 277 (2002), pp. 21749–21758
- ↑ Wegener, K.L. et al., Cell (2007) 128(1):171-82
See also
- Actin-binding protein
- Merlin (protein) an acronym for "Moesin-Ezrin-Radixin-Like Protein"
External links
Proteins of the cytoskeleton | |
|---|---|
| Microfilaments | Actins - Actin-binding proteins - Actinin - Arp2/3 complex - Cofilin - Destrin - Gelsolin - Myosins - Profilin - Tropomodulin - Troponin (T, C, I) - Tropomyosin - Wiskott-Aldrich syndrome protein |
| Intermediate filaments | type 1 and 2 (Cytokeratin, type I, type II) - type 3 (Desmin, GFAP, Peripherin, Vimentin) - type 4 (Internexin, Nestin, Neurofilament, Synemin, Syncoilin) - type 5 (Lamin A, B) |
| Microtubules | Dyneins - Kinesins - MAPs (Tau protein, Dynamin) - Tubulins - Stathmin - Tektin |
| Catenins | Alpha catenin - Beta catenin - Plakoglobin (gamma catenin) - Delta catenin |
| Nonhuman | Major sperm proteins - Prokaryotic cytoskeleton (Crescentin, FtsZ, MreB) |
| Other | APC - Dystrophin (Dystroglycan) - plakin (Desmoplakin, Plectin) - Spectrin - Talin - Utrophin - Vinculin |
Animal intercellular signaling peptides and proteins | |
|---|---|
| Growth factors | Epidermal growth factor - Fibroblast growth factor (FGF2) - Nerve growth factor - Platelet-derived growth factor - Transforming growth factor (TGFα, TGFβ, TGFβ pathway) |
| Other | Hedgehog (Sonic hedgehog) - Integrin - JAK/STAT (JAK/STAT) - MAPK/ERK pathway (MAPK/ERK) - NF-κB - Notch (1, 2, 3) - p53 - Wnt (WNT4, Frzb) |
Transmembrane receptors: immune receptors | |
|---|---|
| Cytokine receptor | Type I: interleukin (IL-2, IL-3) - CSF (Erythropoietin, GM-CSF, G-CSF) - Glycoprotein 130/Oncostatin M - Leukemia inhibitory factor - common subunits (Common gamma chain, CSF2RB) Type II: interleukin (IL22RA2) - interferon (IFNAR, IFNGR) |
| Pattern recognition/Toll-like | TLR 1 - TLR 2 - TLR 3 - TLR 4 - TLR 5 - TLR 6 - TLR 7 - TLR 8 - TLR 9 - TLR 10 |
| Fc receptor | ε (FcεRI, FcεRII) - γ (FcγRI, FcγRII, FcγRIII) - α/μ (FcαRI, Fcα/μR) - Neonatal |
| Lymphocyte homing receptor | CD44 - L-selectin - VLA-4 - LFA-1 |
| other | Antigen receptor (B-cell, T cell) - Complement - Formyl peptide - Immunophilins - Integrin - Killer-cell immunoglobulin-like - Scavenger |
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