What is parvin?
The parvins are a family of actin binding proteins (known as α-, β- and γ-parvin in mammals) that are members of the actin linking functional module at cell-matrix adhesion sites (reviewed in [1]). Parvin is a small protein (42 kDa) that contains a variable amino terminus followed by two actin-binding domains (ABDs) each composed from two calponin homology (CH) domains [2]. Although CH domains are a common feature shared between members of the α-actinin superfamily (reviewed in [3]), the ABDs of parvin are unique and more closely related to fimbrin, which further separates the parvins into a separate family within the α-actinin superfamily [2]. Furthermore, the CH domains of parvin were suggested to have evolved for specifically interacting with non-actin targets at sites of focal adhesion assembly; for example, recruitment of parvin to focal adhesions (FAs) requires an association with paxillin via a paxillin-binding sequence (PBS) motif contained within second CH domain of parvin [4]. Similar to other members of the α-actinin superfamily, α-parvin (aka actopaxin) may function as a dimer [5].
Parvin localization and functionParvin is found in several cell types and at many locations in the cell such as: the leading edge of migrating cells and at sites of growing adhesions; it extends from mature FAs; and it partially localizes with stress fibers [2][4]. Parvin co-localizes completely with talin in FAs and with fibers along the cell body [2]. As parvin is not usually found along the entire length of stress fibers [4], these central fibers more likely resemble tensin-rich fibrillar adhesions (FBs) [6]. Parvin is a member of a triad known as IPP (ILK-PINCH-parvin) which controls the maturation of cell-matrix adhesions by forming a permissive platform for tensin recruitment [7]. Parvin contains numerous potential phosphorylation consensus sequences for kinases such as protein kinase C [4] and extracellular signal-regulated protein kinase [8]; phosphoryation of parvin increases during cell adhesion/spreading [8].
References
- Sepulveda JL, and Wu C. The parvins. Cell. Mol. Life Sci. 2006; 63(1):25-35. [PMID: 16314921]
- Olski TM, Noegel AA, and Korenbaum E. Parvin, a 42 kDa focal adhesion protein, related to the alpha-actinin superfamily. J. Cell. Sci. 2001; 114(Pt 3):525-38. [PMID: 11171322]
- Sjöblom B, Ylänne J, and Djinović-Carugo K. Novel structural insights into F-actin-binding and novel functions of calponin homology domains. Curr. Opin. Struct. Biol. 2008; 18(6):702-8. [PMID: 18952167]
- Nikolopoulos SN, and Turner CE. Actopaxin, a new focal adhesion protein that binds paxillin LD motifs and actin and regulates cell adhesion. J. Cell Biol. 2000; 151(7):1435-48. [PMID: 11134073]
- Wang X, Fukuda K, Byeon I, Velyvis A, Wu C, Gronenborn A, and Qin J. The structure of alpha-parvin CH2-paxillin LD1 complex reveals a novel modular recognition for focal adhesion assembly. J. Biol. Chem. 2008; 283(30):21113-9. [PMID: 18508764]
- Zamir E, Katz M, Posen Y, Erez N, Yamada KM, Katz BZ, Lin S, Lin DC, Bershadsky A, Kam Z, and Geiger B. Dynamics and segregation of cell-matrix adhesions in cultured fibroblasts. Nat. Cell Biol. 2000; 2(4):191-6. [PMID: 10783236]
- Stanchi F, Grashoff C, Nguemeni Yonga CF, Grall D, Fässler R, and Van Obberghen-Schilling E. Molecular dissection of the ILK-PINCH-parvin triad reveals a fundamental role for the ILK kinase domain in the late stages of focal-adhesion maturation. J. Cell. Sci. 2009; 122(Pt 11):1800-11. [PMID: 19435803]
- Clarke DM, Brown MC, LaLonde DP, and Turner CE. Phosphorylation of actopaxin regulates cell spreading and migration. J. Cell Biol. 2004; 166(6):901-12. [PMID: 15353548]