Requirements for the localization of nesprin-3 at the nuclear envelope and its interaction with plectin.
The outer nuclear membrane proteins nesprin-1 and nesprin-2 are retained at the nuclear envelope through an interaction of their klarsicht/ANC-1/syne homology (KASH) domain with Sun proteins present at the inner nuclear membrane. We investigated the requirements for the localization of nesprin-3alpha at the outer nuclear membrane and show that the mechanism by which its localization is mediated is similar to that reported for the localization of nesprin-1 and nesprin-2: the last four amino acids of the nesprin-3alpha KASH domain are essential for its interaction with Sun1 and Sun2. Moreover, deletion of these amino acids or knockdown of the Sun proteins results in a redistribution of nesprin-3alpha away from the nuclear envelope and into the endoplasmic reticulum (ER), where it becomes colocalized with the cytoskeletal crosslinker protein plectin. Both nesprin-3alpha and plectin can form dimers, and dimerization of plectin is required for its interaction with nesprin-3alpha at the nuclear envelope, which is mediated by its N-terminal actin-binding domain. Additionally, overexpression of the plectin actin-binding domain stabilizes the actin cytoskeleton and prevents the recruitment of endogenous plectin to the nuclear envelope. Our studies support a model in which the actin cytoskeleton influences the binding of plectin dimers to dimers of nesprin-3alpha, which in turn are retained at the nuclear envelope through an interaction with Sun proteins.
Ketema
Mirjam
M
Division of Cell Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
Wilhelmsen
Kevin
K
Kuikman
Ingrid
I
Janssen
Hans
H
Hodzic
Didier
D
Sonnenberg
Arnoud
A
D000818:Animals; D002460:Cell Line; D019281:Dimerization; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D009685:Nuclear Envelope / Q000378:metabolism*; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051190:Plectin / Q000737:chemistry / Q000378:metabolism*; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020836:Protein Structure, Quaternary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D034501:Telomere-Binding Proteins / Q000235:genetics / Q000378:metabolism
D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D051190:Plectin; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; C464932:SUN1 protein, mouse; C520338:Sun2 protein, mouse; D034501:Telomere-Binding Proteins; C507800:nesprin-3 protein, mouse