Structure of three high voltage-activated calcium channel α₁ subunits from Schistosoma mansoni

Abstract

Voltage-gated calcium (Ca2+) channels contribute to impulse propagation in excitable cells and also regulate intracellular levels of Ca2+. High voltage-activated (HVA) Ca2+ channels are heteromultimeric membrane proteins. The pore-forming, voltage-sensing subunit is the alpha1 subunit. We have cloned 3 HVA Ca2+ channel alpha1 subunit cDNAs from Schistosoma mansoni. One of these sequences most closely resembles the L-type class of HVA alpha1 subunits. The other two sequences are most closely related to non L-type alpha1 subunits. These schistosome alpha1 subunits have many of the features common to HVA Ca2+ channels, but also have distinct structural motifs. Analysis of the structural and functional properties of schistosome Ca2+ channel subunits may provide information about these critical components of excitable cells.

Expression and Modulation of an Invertebrate Presynaptic Calcium Channel α1 Subunit Homolog

“…Invertebrate species do not appear to contain the same structural diversity of vertebrate calcium channel genes in their genomes and, with one possible exception (16), possess only single homologs of the three major calcium channel families, Ca v 1, Ca v 2, and Ca v 3 (12,17). Invertebrate Ca v 2 representatives are considered functional as well as structural correlates of both mammalian N-(Ca v 2.2) and P/Q-type (Ca v 2.1) calcium channels (12,17).…”

Schistosome Calcium Channel β Subunits

“…4). Previously we have cloned three high voltage-activated Ca 2ϩ channel ␣ 1 subunit cDNAs from Schistosoma mansoni (5). Here, we report the cloning and expression of two Ca 2ϩ channel ␤ subunits from Schistosoma japonicum and S. mansoni.…”

“…These differences would be independent of whether the channel is L-type or non-L-type. For example, schistosome and other flatworm L-type ␣ 1 subunits have a non-charged residue at a conserved negatively charged site in the Domain I pore region (5). Ca v 2.3, but not CyCa v 1, also has a non-charged residue at that site.…”

Effects of L-type Ca2+ channel antagonists on in vitro excystment of Paragonimus ohirai metacercariae induced by sodium cholate

“…L-type Ca 2+ channels are present in the former membrane, are voltage-dependent, and are involved in muscle contraction, endocrine secretion, and gene transcription in vertebrates (Catterall 2000). As well as in vertebrates, the presence of Ltype Ca 2+ channels has been reported in the trematode Schistosoma mansoni (Kohn et al 2001) and other invertebrates (Jeziorski et al 2000).…”