Amphipathic alpha-helical antimicrobial peptide with potent activity against Gram-positive bacteria, weak activity against Gram-negative bacteria, and moderate activity against fungi (PubMed:9022710, PubMed:15513914, PubMed:16867990, PubMed:18255189, PubMed:18370376). Mainly acts by causing membrane permeabilization (Probable). Is also able to kill S.aureus (both wild-type and MRSA) that are internalized in human keratinocytes without injuring host cells (PubMed:24514087). Rapidly inactivates both channel catfish herpesvirus (ED(50)=15 uM) and frog virus 3 (ED(50)=58 uM) over a wide temperature range (PubMed:15193922). Also displays anti-leishmania activity by damaging parasite membrane (PubMed:15513914, PubMed:25668079). Acts synergistically with temporin-L which improves temporin-1Ta activity by preventing its self-association in lipopolysaccharides (LPS) (PubMed:16867990). Does not show hemolytic activity (PubMed:15513914). In vitro, stimulates insulin release from pancreatic beta-cells in a dose-dependent manner without increasing intracellular calcium, protects beta-cells against cytokine-induced apoptosis and augments beta-cells proliferation (PubMed:29349894). In vivo, intraperitoneal injection together with a glucose load into mice does not have effect on plasma glucose levels (PubMed:29349894). In vivo, when tested on mice with methicillin-resistant S.aureus (MRSA)-infected wounds, this peptide inhibits bacterial growth and shows wound healing effect (PubMed:18255189). In vitro, promotes cell migration and wound healing (PubMed:24514087). Forms helical oligomeric structures in LPS lipids, the major constituent of Gram-negative bacteria outer membrane (Probable). Adopts monomeric helical conformations when bound to bacterial (anionic) and eukaryotic (zwitterionic) model membranes (PubMed:18370376). In Gram-positive bacterial mimetic membranes, the aggregation is weakly pronounced, and penetration proceeds more rapidly and is deeper than in Gram-negative bacterial mimetic membranes where aggregation is high (By similarity). Self-association is prevented by temporin-L (PubMed:16867990). Expressed by the skin glands. Adopts helical conformation in LPS micelles fro residues L4-I12. Could be used to protect potato plants from fungi Phytophthora infestans, Phytophthora erythroseptica and bacterium Erwinia carotovora, since the analog N-terminally modified MsrA3 (F1MASRHMF), when expressed in potato plants, conveys strong resistance to late blight and pink rot phytopathogens in addition to the bacterial pathogen Erwinia carotovora. Transgenic tubers remained disease-free during storage for more than 2 years. Is an attractive candidate for the generation of new therapeutics to treat S.aureus-related epithelial (skin) infections. It has (i) a long-lasting existence in nature as active molecule which is able to exert a direct antimicrobial activity, which should guarantee the success of the antimicrobial efficacy of temporin-based anti-infective agents; (ii) a membrane-perturbing activity on bacteria, which should limit the induction of microbial resistance; (iii) the ability to kill both reference S.aureus and MRSA strains, once internalized by human epidermal cells and to treat them; (iv) the ability to stimulate migration of these cells; (v) a chemoattractic property for human monocytes; (vi) an exogenous (nonmammalian) nature, which should allow beneficial effects in clinical medicine, reducing the possible risk of inducing an autoimmune response; and, (vii) a small size, which should allow a low production cost. Belongs to the frog skin active peptide (FSAP) family. Temporin subfamily.