The small GTP-binding protein rab4 is associated with early endosomes

Journal Article · Mon Jul 15 00:00:00 EDT 1991 · Proceedings of the National Academy of Sciences of the United States of America; (United States)

DOI:https://doi.org/10.1073/pnas.88.14.6313· OSTI ID:6096682

van der Sluijs, P; Hull, M; Mellman, I ^[1]; Zahraoui, A; Tavitian, A ^[2]; Goud, B ^[3]

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1. Yale Univ. School of Medicine, New Haven, CT (United States)
2. INSERM U 248, Paris (France)
3. Unite de Genetique Somatique, Paris (France)

Small GTP-binding proteins of the rab family have been implicated as playing important roles in controlling membrane traffic on the biosynthetic and endocytic pathways. The authors demonstrate that a distinct rab protein, rab4p, is associated with the population of early endosomes involved in transferrin-receptor recycling. An antibody to human rab4p was found to detect a doublet of {approx} 24-kDa proteins on immunoblots from various cell types. Seventy-five percent of these proteins were tightly membrane bound and could be released only by detergent treatment. Upon isolation of early endosomes, late endosomes, and lysosomes, by free-flow electrophoresis and Percoll density-gradient centrifugation, most (70%) of the rab4p was found to cofractionate with early endosomes and endocytic vesicles containing {sup 125}-labeled transferrin. The rab proteins previously localized to the endoplasmic reticulum and/or Golgi apparatus were not found in these fractions. They also localized rab4p to tansferrin-receptor-containing early endosomes by immunofluorescence after expression of rab4p cDNA. The association of rab4p with early endosomes and other vesicles involved in the intracellular tansport of transferrin receptor suggests that rab4p may play a role in regulating the pathway of receptor recycling.

• OSTI ID: 6096682
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (United States), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (United States) Vol. 88:14; ISSN PNASA; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
BETA DECAY RADIOISOTOPES
CELL CONSTITUENTS
CELL MEMBRANES
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELECTROPHORESIS
ENDOPLASMIC RETICULUM
GLOBULINS
GLOBULINS-BETA
HELA CELLS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MEMBRANE PROTEINS
MEMBRANES
METALLOPROTEINS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PROTEINS
RADIOISOTOPES
RADIORECEPTOR ASSAY
RECEPTORS
TRACER TECHNIQUES
TRANSFERRIN