Tektins are cytoskeletalproteins found in cilia and flagella as structural components of outer doublet microtubules. They are also present in centrioles and basal bodies. They are polymeric in nature, and form filaments.
Tektin filaments are 2 to 3 nm diameter with two alpha helical segments. They have the consensus amino acid sequence of 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 a supercoiled state.  This structure of tektins suggests that they are evolutionarily related to intermediate filaments.
Tektins as integral components of microtubules are essential for their structural integrity. A mutation in the tektin-t genes may lead to defects in flagellar activity which could manifest, for instance, as immotility of sperm leading to male infertility.  Tektins are thought to be involved in the assembly of the basal body.  The study of tektins has also been found to be useful in phylogeny, to establish evolutionary relationship between organisms.Amino acid sequences of tektins are well conserved, with significant similarity between mouse and human homologs.
^ 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
^ Peter W. Settera, Erika Malvey-Dornb, Walter Steffenc, Raymond E. Stephensd, Richard W. Linck; Tektin interactions and a model for molecular functions; Experimental Cell Research, Volume 312, Issue 15, 10 September 2006, Pages 2880-2896; doi:10.1016/j.yexcr.2006.05.014
^ J M Norrander, L A Amos, and R W Linck; 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. 1992 September 15; 89(18): 8567–8571.
^ Naoko Iguchi, Hiromitsu Tanaka, Yoshihiro Nakamura, Masami Nozaki, Tsutomu Fujiwara and Yoshitake Nishimune; Cloning and characterization of the human tektin-t gene; Molecular Human Reproduction, Vol. 8, No. 6, 525-530, June 2002
^ Magnus Larssona, Jan Norranderb, Susanne Gräslunda, Eva Brundellc, Richard Linckb, Stefan Ståhla, Christer Höög; 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; European Journal of Cell Biology, Volume 79, Issue 10, October 2000, Pages 718-725; doi:10.1078/0171-9335-00097
^ Alaine Whinnett, Andrew V. Z. Brower, Ming-Min Lee, Keith R. Willmott, and James Mallet; Phylogenetic Utility of Tektin, a Novel Region for Inferring Systematic Relationships Among Lepidoptera; Annals of the Entomological Society of America, Volume 98, Issue 6 (November 2005), Article: pp. 873–886; DOI: 10.1603/0013-8746(2005)098[0873:PUOTAN]2.0.CO;2