From the origin and molecular diversity of the amastins, to the origin and diversity of intracellular parasitism from human Trypanosomatids
Authors: Padilla Alejandro 
Published: November 2021

The large families of amastins from Leishmania donovani, L. infantum, L. major, L. braziliensis and Trypanosoma cruzi are strongly associated with the evolution of intracellular parasitism of rich cells in human MHC.1 molecules such as the macrophages, dendritic cells, and Langerhans cells by these parasites, recognize the MHC-1 molecules as host receptor. The internalization and transport of the paraste in the cytoplas of infected cell is facilitated by the MHC-1 recycle and endosome formation drag and transport the parasite in the cytoplasm of infected cell. The microbody amastins participate as coreceptor potency the infection, the tropism of L. major and L. braziliensis by the cells from the skin is facilitated by two molecular interactions, the first molecular interaction is faclitated by the amastins interact the human MHC-1 molecules, and the second molecular interaction is facilitated by the numerous microbody amastins; which also participate in the biogenesis of the small prasitophorous vcuole from L. major, and large parasitophorous vacuole from L. braziliensis.

All amastins from these parasites developed deactivation domains, in different grade L. donovani develop an amastin surface coat specialized in deactivation of infected macrophages heavily glycosylated developed 38 amastins with 38 glycosylation Asp. N-Glycosylation sites and 45 N-glucosamina glycosylation sites, whereas L. infantum, L. major and L. braziliensis developed one half of glycosylated amastins in asparagine N-glycosylation sites, and T. cruzi did not developed none glycosylated amastin.

The amastins surface coat from L. donovani is rich in phosphorylation sites, developed 45 amastins with 45 casein kinase II phosphorylations sites, and 48 amastins with 48 protein kinase phosphorylation sites. L. infantum, L. braziliensis, and T. cruzi developed 32, 42, and 8 amastins, with 94, 114, 21 casein kinase II phosphorylation sites; in similar way developed 35,38, 11 amastins with 89,78, and 22 protein kinase phosphorylation sites. The family of amastins from L. donovani develop 137 phosphoserines. and 128 phosphothreonine, L. major developed 14 phosphoserine and 4 phosphothreonine; L. infantum 1 phophoserine and 7 phosphothreonine; L. braziliensis did not developed phosphoserine and phosphothreonine and T. cruzi 4 phosphoserine and 4 phosphothreonine. The results show that amastin surface coat is equiped with numerous phosphorylations sites atractive for phosphohrylases from the infected host contribute with the dephosphorylation and deactivation of infectetd host cells.

The amastins from L. major develop a membrane amastin with laminin G domain, which can interact with the collagen and heparin sulfate proteoglycan sites from the extracellular matrix of the skin tissue. Furthermore develop 14 amastins with tyrosine sulfation site, evade the activation of receptor of chemokines and the activation of the immune response by chemokines.

There is an alternative mechanism of polarization of the immune response from protective TH1 to non protective TH2.

The parasite nutrition is mediated by amastins that dissimilate the MHC-1 molecules and other subsets of proteins, the dissimilation products can be translocated through of the parasite cell membrane and employed as nutrient source.