Da. Mathers et al., THE MAJOR SURFACE PROTEIN COMPLEX OF TREPONEMA-DENTICOLA DEPOLARIZES AND INDUCES ION CHANNELS IN HELA-CELL MEMBRANES, Infection and immunity, 64(8), 1996, pp. 2904-2910
The oral spirochete Treponema denticola is closely associated with per
iodontal diseases in humans. The 53-kDa major surface protein (Msp) lo
cated in the outer membrane of T. denticola serovar a (ATCC 35405) has
both pore-forming activity and adhesin activity. We have used standar
d patch clamp recording methods to study the effects of a partially pu
rified outer membrane complex containing Msp on HeLa sells. The Msp co
mplex was free of the chymotrypsin-like proteinase also found in the o
uter, membrane of T. denticola. Msp bound to several HeLa cell protein
s, including a 65-kDa surface protein and a 96-kDa cytoplasmic protein
. The Msp complex depolarized and increased the conductance of the HeL
a cell membrane in a manner which was not strongly selective for Na+,
K+, Ca2+, and Cl- ions. Cell-attached patches of Hela cell membrane ex
posed to Msp complex exhibited short-lived channels with a slope condu
ctance of 0.4 nS in physiologically normal saline. These studies show
that Msp binds both a putative epithelial cell surface receptor and cy
toplasmic proteins and that the Msp complex can form large conductance
ion channels in the cytoplasmic membrane of epithelial cells. These p
roperties may contribute to the cytopathic effects of T. denticola on
host epithelial cells.