keratin, type 1 cytoskeletal 28 (cytokeratin-28, keratin-28, type 1 inner root sheath-specific keratin-K25irs4, KRT28, KRT25D)

Function

• assembly of types 1 & 2 keratin protein complexes & the formation of keratin intermediate filaments in the inner root sheath
• heterotetramer of two type1 & two type 2 keratins

Structure

belongs to the intermediate filament family

Compartment

cytoplasm (putative)

Expression

• strongly expressed in skin & scalp, & weak expression observed in thymus
• in the hair follicle, expressed in Henle layer, Huxley layer & in the irs cuticle
• expression extends from the bulb region up to the point of differentiation into the three layers
• present in the medulla of beard hair (at protein level)

Notes

• 2 types of cytoskeletal & microfibrillar keratin: 1 (acidic; 40-55 kD) 2 (neutral to basic; 56-70 kD)

More general terms

• cytokeratin, epithelial keratins or soft alpha-keratins

Database

• UniProt: http://www.uniprot.org/uniprot/Q7Z3Y7.html