High impact information on Tig

• Cell spreading assays detect no interactions of this mutant tiggrin with PS2 integrins [1].
• The PS2 integrin ligand tiggrin is required for proper muscle function in Drosophila [1].
• Transgenes expressing a mutant tiggrin, whose Arg-Gly-Asp (RGD) integrin recognition sequence has been mutated to Leu-Gly-Ala (LGA) show much reduced, but significant, rescuing ability [1].
• Tiggrin is a novel extracellular matrix ligand for the Drosophila PS2 integrins [1].
• Transgenes expressing tiggrin are capable of rescuing tiggrin mutant phenotypes [1].

Biological context of Tig

• The tiggrin gene is at chromosome locus 26D1-2 and is expressed by embryonic hemocytes and fat body cells [2].
• Most flies lacking tiggrin die as larvae or pupae [1].
• Muscle contraction waves that extend the length of the larvae are much slower in tiggrin mutants [1].

Anatomical context of Tig

• We report the biochemical purification and cloning of tiggrin, a novel extracellular matrix protein from Drosophila [2].
• Immune induction has been shown for three of the latter, namely Tiggrin and two unknown proteins (GC15825 and CG15293) that we now propose function in hemolymph clotting [3].
• Next, we genetically manipulated the fate of the muscles and the epidermal muscle attachment cells, which demonstrated that muscles have the primary role in recruiting tiggrin to the tendon matrix and that cell-cell contact is necessary for this recruitment [4].
• Thus we propose that the inherent polarity of the muscle cells leads to a molecular specialization of their ends, and interactions between the ends produces an integrin-independent tiggrin receptor [4].

Associations of Tig with chemical compounds

• We have examined this by testing whether the PS2 integrin can recruit tiggrin to ectopic locations within the Drosophila embryo [4].

Other interactions of Tig

• Previous work has shown that the PS integrins are not required for tiggrin localization, suggesting that there is redundancy among tiggrin receptors [4].
• Splice variants of the Drosophila PS2 integrins differentially interact with RGD-containing fragments of the extracellular proteins tiggrin, ten-m, and D-laminin 2 [5].

References