Tektin
| Tektin family | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| Symbol | Tektin | ||||||||
| Pfam | PF03148 | ||||||||
| InterPro | IPR000435 | ||||||||
| |||||||||
Tektinsarecytoskeletalproteinsfound inciliaandflagellaas structural components of outer doubletmicrotubules.They are also present incentriolesandbasal bodies.They are polymeric in nature, and form filaments.[1]
They includeTEKT1,TEKT2,TEKT3,TEKT4,TEKT5.
Structure
[edit]Tektin filaments are 2 to 3 nm diameter with twoalpha helicalsegments. They have theconsensus amino acid sequenceof RPNVELCRD. Different types of tektins, designated as A (53 kDa), B (51 kDa), C (47 kDa) form dimers, trimers and oligomers in various combinations and are also associated with tubulin in the microtubule. Tektins A and B form heteropolymeric protofilaments whereas tektin C forms homodimers. Tektin filaments are present in asupercoiledstate.[2]This structure of tektins suggests that they are evolutionarily related tointermediate filaments.[3]
The proteins are predicted to form extended rods composed of 2 alpha- helical segments (~180 residues long) capable of forming coiled coils, interrupted by non-helical linkers.[4]The 2 segments are similar in sequence, indicating a gene duplication event. Along each tektin rod, cysteine residues occur with a periodicity of ~8 nm, coincident with the axial repeat of tubulin dimers in microtubules.[4]It is proposed that the assembly of tektin heteropolymers produces filaments with repeats of 8, 16, 24, 32, 40, 48 and 96 nm, generating the basis for the complex spatial arrangements of axonemal components.[4]
Function
[edit]Tektins as integral components of microtubules are essential for their structural integrity. A mutation in thetektin-tgenesmay lead to defects in flagellar activity which could manifest, for instance, as immotility ofspermleading tomale infertility.[5]Tektins are thought to be involved in the assembly of thebasal body.[6]
The study of tektins has also been found to be useful inphylogeny,to establish evolutionary relationship between organisms.[7]
Amino acidsequences of tektins are well conserved, with significant similarity between mouse and humanhomologs.
See also
[edit]References
[edit]- ^MA Pirner and RW Linck;Tektins are heterodimeric polymers in flagellar microtubules with axial periodicities matching the tubulin lattice;J. Biol. Chem., Vol. 269, Issue 50, 31800-31806, Dec, 1994
- ^Setter PW, Malvey-Dorn E, Steffen W, Stephens RE, Linck RW (September 2006). "Tektin interactions and a model for molecular functions".Exp. Cell Res.312(15): 2880–96.doi:10.1016/j.yexcr.2006.05.014.PMID16831421.
- ^Norrander JM, Amos LA, Linck RW (September 1992)."Primary structure of tektin A1: comparison with intermediate-filament proteins and a model for its association with tubulin".Proc. Natl. Acad. Sci. U.S.A.89(18): 8567–71.Bibcode:1992PNAS...89.8567N.doi:10.1073/pnas.89.18.8567.PMC49961.PMID1528862.
- ^abcAmos LA, Norrander JM, Perrone CA, Linck RW (1996). "Structural comparison of tektins and evidence for their determination of complex spacings in flagellar microtubules".J. Mol. Biol.257(2): 385–397.doi:10.1006/jmbi.1996.0170.PMID8609631.
- ^Iguchi N, Tanaka H, Nakamura Y, Nozaki M, Fujiwara T, Nishimune Y (June 2002)."Cloning and characterization of the human tektin-t gene".Mol. Hum. Reprod.8(6): 525–30.doi:10.1093/molehr/8.6.525.PMID12029069.
- ^Larsson M, Norrander J, Gräslund S, Brundell E, Linck R, Ståhl S, Höög C (October 2000). "The spatial and temporal expression of Tekt1, a mouse tektin C homologue, during spermatogenesis suggest that it is involved in the development of the sperm tail basal body and axoneme".Eur. J. Cell Biol.79(10): 718–25.doi:10.1078/0171-9335-00097.PMID11089920.
- ^Whinnett A, Brower AVZ, Lee M-M, Willmott KR, Mallet J (June 2005). "Phylogenetic Utility of Tektin, a Novel Region for Inferring Systematic Relationships Among Lepidoptera".Annals of the Entomological Society of America.98(6): 873–886.doi:10.1603/0013-8746(2005)098[0873:PUOTAN]2.0.CO;2.S2CID16054233.