Table 1.

Properties of L1, A27, and A28, MV proteins which are involved in cell entry

		L1	A27	A28
Blocking of entry by antibodies		+	+	+
Binding by soluble proteins to various targets	cells	++	++	−
	heparin a	+/−	+	−
	GAG-deficient sog9 cells	+	+	n/a
	cells in presence of soluble GAGs	+	+	n/a
Blocking of entry by soluble proteins	GAG-expressing cells	++	++	−
	GAG-deficient sog9 cells	++	+/−	−
Blocking of virus binding by soluble proteins	GAG-expressing cells	++	++	−
	GAG-deficient sog9 cells	++	−	−
Entry phenotype of null-virus		defective in entry and VACV-induced cell-cell fusion b or assembly c	reduced infectivity but cell-binding unaffected d	defective in entry and VACV-induced cell-cell fusion e

^aAs determined by affinity chromatography using agarose beads conjugated to heparin (Supplementary Fig. 2)

^b(Bisht, Weisberg, and Moss, 2008)

^c(Ravanello and Hruby, 1994)

^dDue to the existence of other MV attachment proteins which can compensate for the loss in HSPG-binding by A27 (e.g. D8 or L1) (Hsiao, Chung, and Chang, 1999)

^e(Senkevich, Ward, and Moss, 2004)