EVIDENCE FOR A HIGH-AFFINITY, SATURABLE, PRENYLATION-DEPENDENT P21(HA-RAS) BINDING-SITE IN PLASMA-MEMBRANES

Oncogenic p21(ras) proteins can only exert their stimulation of cellul ar proliferation when plasma membrane-associated. This membrane associ ation has an absolute requirement for post-translational modification with isoprenoids. The mechanism by which isoprenoids participate in th e specific association of p21(ras) with plasma membranes is the subjec t of this report. We present in vitro evidence for a plasma membrane b inding protein for p21(ras) that can recognize the isoprenoid substitu ent and, therefore, may facilitate the localization of p21(ras).