Keratin-associated protein 4-2 (KRTAP4-2)

Keratin-associated protein 4-2 (KRTAP4-2) is a member of the keratin-associated protein (KAP) family, specifically classified within the ultrahigh sulfur KAP subfamily[1][3]. These proteins form the matrix that surrounds and cross-links keratin intermediate filaments in the hair cortex, largely contributing to the physical properties of hair fibers[1][2]. The high cysteine content of KRTAP4-2 enables extensive disulfide bond cross-linking with hair keratins, imparting rigidity and resistance to the hair shaft[1]. KRTAP4-2 is protein-coding, not an enzyme or receptor; its primary function is structural, with no direct involvement in signaling, transport, or catalytic activity[1]. The gene is localized on human chromosome 17q12–q21 and is surrounded by a cluster of similar keratin-associated protein genes[1][3][6]. There is no clinical use for drugs or as a biomarker; its role is purely as a component of hair fiber biology.

Other names

Keratin-associated protein 4-2KRTAP4-2KAP4.2Keratin-associated protein 4.2Ultrahigh sulfur keratin-associated protein 4.2KRTAP4.2

None known (no drugs or biologics reported; KRTAP4-2’s function is non-enzymatic structural)