KRTAP5-7 Activators

KRTAP5-7 play a pivotal role in modulating the function of this hair shaft reinforcement protein through various biochemical pathways. Phorbol 12-myristate 13-acetate (PMA) and 12-O-Tetradecanoylphorbol-13-acetate (TPA) both activate protein kinase C (PKC), a key player in the phosphorylation of many proteins including KRTAP5-7. Activation of PKC leads to the phosphorylation of KRTAP5-7, thereby enhancing its function in the hair shaft. Similarly, Bryostatin 1, through its interaction with PKC, and Phosphatidylserine, by modulating PKC activity, can also facilitate the phosphorylation and subsequent activation of KRTAP5-7. Forskolin and Dibutyryl-cAMP elevate intracellular cAMP levels, which in turn activate protein kinase A (PKA). PKA is another kinase that can target KRTAP5-7, leading to its phosphorylation and activation.

Ionomycin and Thapsigargin alter calcium concentrations within cells, which can initiate the activation of calcium-dependent kinases that may target KRTAP5-7. Ionomycin, being a calcium ionophore, increases intracellular calcium levels, while Thapsigargin disrupts calcium homeostasis by inhibiting the sarcoplasmic/endoplasmic reticulum Ca2+ ATPase (SERCA). Both of these alterations in calcium signaling can lead to the activation of KRTAP5-7. In addition, Calyculin A and Okadaic Acid, by inhibiting protein phosphatases PP1 and PP2A, prevent the dephosphorylation of KRTAP5-7, thereby maintaining it in an active phosphorylated state. Cantharidin, another protein phosphatase inhibitor, operates via a similar mechanism to sustain the active form of KRTAP5-7. Retinoic Acid, though not directly involved in phosphorylation, can influence cellular differentiation processes that may upregulate enzymes responsible for KRTAP5-7 activation. These chemical activators collectively ensure that KRTAP5-7 retains its functional phosphorylation, crucial for its role in reinforcing the hair shaft structure.