Microtubule inner protein (MIP) part of the dynein-decorated doublet microtubules (DMTs) in cilia and flagellar axoneme (PubMed:36191189). Plays a key role in the assembly or attachment of the inner dynein arm to microtubules in sperm flagella and tracheal cilia. Forms filamentous polymers in the walls of ciliary and flagellar microtubules. {ECO:0000250|UniProtKB:Q922G7, ECO:0000269|PubMed:36191189}. This is the function of TEKT2 (tektin 2, Ensembl gene identifier ENSG00000092850).