Byline: Hua. Gong, Huitong. Zhou, Grant. McKenzie, Jonathan. Hickford, Zhidong. Yu, Stefan. Clerens, Jolon. Dyer, Jeffrey. Plowman
Keratin associated proteins (KAPs) are a class of proteins that associate with keratin intermediate filament proteins through disulphide linkages to give fibres such as hair and wool their unique properties. Up to 90 proteins from some 25 families have been identified and this does not include polymorphic variants of individual proteins within these families. The existence of this diverse group of proteins has been known for some 75 years but, despite this, there is still no universally accepted nomenclature for them. This paper sets out the case for revising the current system to deal with this nomenclature issue.
The major structural protein components of hair and wool are the longitudinally arrayed intermediate filament proteins, more generally known as keratins (KRTs), which are found in the central cortex of the fibre. [sup] Keratin-associated proteins (KAPs), located in the matrix, cross-link with KRTs through a network of disulfide bonds. Their effect on KRT assembly into large arrays (the so-called intermediate filaments) is considered to be crucial and therefore they may affect wool attributes such as strength, inertness and rigidity. [sup]
The KAPs were initially characterised in sheep, but recently understanding of them has been advanced through sequencing of the human genome. This has revealed a large number of KAP genes ( KRTAP s) and they are spread throughout the human genome. Gene sequencing in other mammals has established that analogs of many of the human KRTAPs exist and that these genes are often polymorphic. This polymorphism needs to be considered in naming these genes, but variation in sequence homology between genes from different species adds new complexity to the task of identifying and naming the KAPs and KRTAP s. This suggests the current nomenclature system defined by Powell and Rogers (1994) [sup] needs to be revisited to ascertain its robustness.
The nomenclature of the KAPs has undergone considerable change since their first description in 1934 as "proteins having a higher sulphur content than that of whole wool". [sup] Knowledge...