Structural component of intermediate filaments in the hair follicle (PubMed:16525032). As a type II hair keratin, participates in the formation of keratin intermediate filament networks by forming obligate heterodimers with type I hair keratins (PubMed:16525032). Expressed at early stages of hair differentiation in matrix cells and later in cuticle-forming cells, where it contributes to the structural integrity and mechanical resilience of the hair shaft (PubMed:16525032). . This is the function of KRT85 (keratin 85, Ensembl gene identifier ENSG00000135443).