Two separate motifs cooperate to target stathmin-related proteins to the Golgi complex.
The appropriate targeting of membrane-associated proteins involves a diversity of motifs including post-translational modifications and specific protein sequences. Phosphoproteins of the stathmin family are important regulators of microtubule dynamics, in particular in the developing and mature nervous system. Whereas stathmin is cytosolic, SCG10, SCLIP and the splice variants RB3/RB3'/RB3'' are associated with Golgi and vesicular membranes, through their palmitoylated N-terminal A domains. In order to identify essential motifs involved in this specific targeting, we examined the subcellular distribution of various subdomains derived from domain A of SCG10 fused with GFP. We show that the Golgi localization of SCG10 results from the cooperation of two motifs: a membrane-anchoring palmitoylation motif and a newly identified Golgi-specifying sequence. The latter displayed no targeting activity by itself, but retained a Golgi-specifying activity when associated with another membrane-anchoring palmitoylation motif derived from the protein GAP-43. We further identified critical residues for the specific Golgi targeting of domain A. Altogether, our results give new insight into the regulation of the subcellular localization of stathmin family proteins, an important feature of their physiological functions in differentiating and mature neural cells. More generally we provide new information on essential mechanisms of functional protein subcellular targeting.
Charbaut
Elodie
E
INSERM, U706, Neurosignalisation Moléculaire et Cellulaire, Institut du Fer à Moulin, 17 rue du Fer à Moulin, and Université Pierre et Marie Curie (UPMC), 4 place Jussieu, Paris, 75005 France.
Chauvin
Stéphanie
S
Enslen
Hervé
H
Zamaroczy
Sophie
S
Sobel
André
A
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins; D002462:Cell Membrane / Q000502:physiology; D002478:Cells, Cultured; D004285:Dogs; D019922:GAP-43 Protein / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins; D008868:Microtubule Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D050777:Stathmin
D002352:Carrier Proteins; D019922:GAP-43 Protein; D008565:Membrane Proteins; D008868:Microtubule Proteins; D009414:Nerve Growth Factors; D011993:Recombinant Fusion Proteins; C063314:STMN2 protein, human; D050777:Stathmin; C512848:Stmn2 protein, rat; D049452:Green Fluorescent Proteins