The nonhelical tail domain is involved in promoting KRT5-KRT14 filaments to self-organize into large bundles and enhances the mechanical properties involved in resilience of keratin intermediate filaments in vitro. Heterotetramer of two type I and two type II keratins (By similarity). Forms a disulfide-linked heterodimer (via 2B domains) with KRT5 (via 2B domains) (PubMed:24940650, PubMed:22705788). Forms a heterodimer with KRT1; the interaction is more abundant in the absence of KRT5 (By similarity). Interacts with PLEC isoform 1C, when in a heterodimer with KRT5 (PubMed:24940650). Interacts with TRADD and with keratin filaments (PubMed:11684708). Associates with other type I keratins (PubMed:11724817). Interacts with EPPK1 (By similarity). Interacts with KLHL24 (PubMed:27798626). Expressed in both as a filamentous pattern. Expressed in the corneal epithelium (at protein level) (PubMed:26758872). Detected in the basal layer, lowered within the more apically located layers specifically in the stratum spinosum, stratum granulosum but is not detected in stratum corneum. Strongly expressed in the outer root sheath of anagen follicles but not in the germinative matrix, inner root sheath or hair (PubMed:9457912). Found in keratinocytes surrounding the club hair during telogen (PubMed:9457912). A disulfide bond is formed between rather than within filaments and promotes the formation of a keratin filament cage around the nucleus. Ubiquitinated by the BCR(KLHL24) E3 ubiquitin ligase complex. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. There are two types of cytoskeletal and microfibrillar keratin: I (acidic; 40-55 kDa) and II (neutral to basic; 56-70 kDa). Belongs to the intermediate filament family.