TGM1 and infection: This was because infection upregulates the expression of both TGase1 and TGase3 more highly in the heart with periostial hemocytes than in other tissues16, but perhaps the lack of involvement of TGase1 in heart-associated immune responses is congruent with a previous study that found that TGase1 does not participate in the immune response against malaria parasites, at least in the gut32.