The furin protease cleavage recognition sequence of Sindbis virus PE2 can mediate virion attachment to cell surface heparan sulfate.
Klimstra WB, Heidner HW, Johnston RE. The furin protease cleavage recognition sequence of Sindbis virus PE2 can mediate virion attachment to cell surface heparan sulfate. J Virol. 1999 Aug; 73(8):6299-306.