The clip domain is a structural/regulatory unit in many arthropod serine proteases [1]. The clip domain super-family also includes serine protease homologs (SPHs) [2]. This entry describes clip domains in the SPHs (CLIP subfamily A), which belong to group-3. SPHs usually carry between 1 to 5 clip domains [3]. The most prominent family member of carrying this clip domain is Scarface proteins in drosophila, which bear an inactive catalytic site, representing a subgroup of serine protease homologues (SPH). Loss-of-function induces defects in JNK-controlled morphogenetic events such as embryonic dorsal closure and adult male terminalia rotation [4].

1: Serine proteases and their homologs in the Drosophila melanogaster genome: an initial analysis of sequence conservation and phylogenetic relationships. Ross J, Jiang H, Kanost MR, Wang Y; Gene. 2003;304:117-131. PMID:12568721

2: Clip-domain serine proteases as immune factors in insect hemolymph. Kanost MR, Jiang H; Curr Opin Insect Sci. 2015;11:47-55. PMID:26688791

3: Sequence conservation, phylogenetic relationships, and expression profiles of nondigestive serine proteases and serine protease homologs in Manduca sexta. Cao X, He Y, Hu Y, Zhang X, Wang Y, Zou Z, Chen Y, Blissard GW, Kanost MR, Jiang H; Insect Biochem Mol Biol. 2015;62:51-63. PMID:25530503

4: The Drosophila serine protease homologue Scarface regulates JNK signalling in a negative-feedback loop during epithelial morphogenesis. Rousset R, Bono-Lauriol S, Gettings M, Suzanne M, Speder P, Noselli S; Development. 2010;137:2177-2186. PMID:20530545