Differential interaction of ADP-ribosylation factors 1, 3, and 5 with rat brain Golgi membranes.
AUTOR(ES)
Tsai, S C
RESUMO
Six mammalian ADP-ribosylation factors (ARFs) identified by cDNA cloning were expressed as recombinant proteins (rARFs) that stimulated cholera toxin ADP-ribosyltransferase activity. Microsequencing of soluble ARFs I and II (sARFs I and II), purified from bovine brain, established that they are ARFs 1 and 3, respectively. Rabbit antibodies (IgG) against sARF II reacted similarly with ARFs 1, 2, and 3 (class I) on Western blots. ARFs 1 and 3 were distinguished by their electrophoretic mobilities. Antiserum against rARF 5 cross-reacted partially with rARF 4 but not detectably with rARF 6 and minimally with class I ARFs. Guanosine 5'-O-(3-thiotriphosphate) (GTP[gamma S]) increased recovery of ARF activity and immunoreactivity in organelle fractions separated by density gradient centrifugation, after incubation of rat brain homogenate with ATP and a regenerating system. ARF 1 accumulated in microsomes plus Golgi and Golgi fractions, whereas ARF 5 seemed to localize more specifically in Golgi; the smaller increment in ARF 3 was distributed more evenly among fractions. On incubation of Golgi with a crude ARF fraction, GTP[gamma S], and an ATP-regenerating system, association of ARF activity with Golgi increased with increasing ATP concentration paralleled by increases in immunoreactive ARFs 1 and 5 and, to a lesser degree, ARF 3. Golgi incubated with GTP[gamma S] and purified ARF 1 or 3 bound more ARF 1 than ARF 3. Based on immunoreactivity and assay of ARF activity, individual ARFs 1, 3, and 5 appeared to behave independently and selectively in their GTP-dependent association with Golgi in vitro.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=50108Documentos Relacionados
- Activation of rat brain phospholipase D by ADP-ribosylation factors 1,5, and 6: separation of ADP-ribosylation factor-dependent and oleate-dependent enzymes.
- Intravesicular acidification correlates with binding of ADP-ribosylation factor to microsomal membranes.
- ADP-ribosylation factor is functionally and physically associated with the Golgi complex.
- ADP-ribosylation factor, a small GTP-binding protein, is required for binding of the coatomer protein beta-COP to Golgi membranes.
- ADP-ribosylation factor and phosphatidic acid levels in Golgi membranes during budding of coatomer-coated vesicles