Alsin is a Rab5 and Rac1 guanine nucleotide exchange factor

Justin D. Topp, Noah W. Gray, Robert D. Gerard, Bruce F Horazdovsky

Research output: Contribution to journalArticle

140 Citations (Scopus)

Abstract

ALS2 is the gene mutated in a recessive juvenile form of amyotrophic lateral sclerosis (ALS2). ALS2 encodes a large protein termed alsin, which contains a number of predicted cell signaling and protein trafficking sequence motifs. To gain insight into the overall function of alsin and to begin to evaluate its role in motor neuron maintenance, we examined the subcellular localization of alsin and the biochemical activities associated with its individual subdomains. We found that the Vps9p domain of alsin has Rab5 guanine nucleotide exchange activity. In addition, alsin interacted specifically with and acted as a guanine nucleotide exchange factor for Rac1. Immunofluorescence and fractionation experiments in both fibroblasts and neurons revealed that alsin is a cytosolic protein, with a significant portion associated with small, punctate membrane structures. Many of these membrane structures also contained Rab5 or Rac1. Upon overexpression of full-length alsin, the overexpressed material was largely cytosolic, indicating that the association with membrane structures could be saturated. We also found that alsin was present in membrane ruffles and lamellipodia. These data suggest that alsin is involved in membrane transport events, potentially linking endocytic processes and actin cytoskeleton remodeling.

Original languageEnglish (US)
Pages (from-to)24612-24623
Number of pages12
JournalJournal of Biological Chemistry
Volume279
Issue number23
DOIs
StatePublished - Jun 4 2004

Fingerprint

Guanine Nucleotide Exchange Factors
Membrane structures
Neurons
Membranes
Cell signaling
Proteins
Guanine Nucleotides
Fibroblasts
Fractionation
Actins
Genes
Pseudopodia
Amyotrophic Lateral Sclerosis
Motor Neurons
Protein Transport
Actin Cytoskeleton
Fluorescent Antibody Technique
Cell Count
Maintenance
Experiments

ASJC Scopus subject areas

  • Biochemistry

Cite this

Topp, J. D., Gray, N. W., Gerard, R. D., & Horazdovsky, B. F. (2004). Alsin is a Rab5 and Rac1 guanine nucleotide exchange factor. Journal of Biological Chemistry, 279(23), 24612-24623. https://doi.org/10.1074/jbc.M313504200

Alsin is a Rab5 and Rac1 guanine nucleotide exchange factor. / Topp, Justin D.; Gray, Noah W.; Gerard, Robert D.; Horazdovsky, Bruce F.

In: Journal of Biological Chemistry, Vol. 279, No. 23, 04.06.2004, p. 24612-24623.

Research output: Contribution to journalArticle

Topp, JD, Gray, NW, Gerard, RD & Horazdovsky, BF 2004, 'Alsin is a Rab5 and Rac1 guanine nucleotide exchange factor', Journal of Biological Chemistry, vol. 279, no. 23, pp. 24612-24623. https://doi.org/10.1074/jbc.M313504200
Topp, Justin D. ; Gray, Noah W. ; Gerard, Robert D. ; Horazdovsky, Bruce F. / Alsin is a Rab5 and Rac1 guanine nucleotide exchange factor. In: Journal of Biological Chemistry. 2004 ; Vol. 279, No. 23. pp. 24612-24623.
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