ADP-ribosylation factor (ARF)-like 4, 6, and 7 represent a subgroup of the ARF family characterized by rapid nucleotide exchange and a nuclear localization signal

Abstract

The novel ARF-like GTPase ARL7 is a close relative of ARL4 and ARL6 (71% and 59% identical amino acids). A striking characteristic of these GTPases is their basic C-terminus which, when fused to the C-terminus of green fluorescent protein (GFP), targets the constructs to the nucleus of transfected COS-7 cells. Full length ARL4 was detected in both nuclear and extranuclear compartments, whereas a construct of ARL4 lacking its C-terminus was excluded from the nucleus. Nucleotide exchange rates of recombinant ARL4, ARL6 and ARL7 were similar and appeared considerably higher than those of other members of the ARF family (ARF1, ARP). It is concluded that ARL4, ARL6 and ARL7 form a subgroup within the ARF family with similar, possibly nuclear, function.