Tectonins I and II are two dominant proteins in the nuclei and nuclear matrix from plasmodia of Physarum polycephalum (Slime mold) and both proteins contain six tandem repeats that are each 33-37 amino acids in length. Homologous repeats are found in L-6, a bacterial lipopolysaccharide-binding lectin from horseshoe crab hemocytes. The repetitive sequences of the tectonins and L-6 are reminiscent of the WD repeats of the beta-subunit of G proteins, suggesting that they form beta-propeller domains. The tectonins may be lectins that function as part of a transmembrane signalling complex during phagocytosis [1]. Tectonin beta-propeller repeat-containing protein 1 (TECPR1) has a critical function during autophagosome maturation and autophagosome-lysosome fusion [2].

1: Cloning and characterization of Physarum polycephalum tectonins. Homologues of Limulus lectin L-6. Huh CG, Aldrich J, Mottahedeh J, Kwon H, Johnson C, Marsh R; J Biol Chem. 1998;273:6565-6574. PMID:9497393

2: A mammalian autophagosome maturation mechanism mediated by TECPR1 and the Atg12-Atg5 conjugate. Chen D, Fan W, Lu Y, Ding X, Chen S, Zhong Q; Mol Cell. 2012;45:629-641. PMID:22342342