The role of keratin filaments during nuclear envelope reassembly in Xenopus egg extracts¹

Abstract

We report here a new structure, named`strings-ofpearls', which are seen to form in Xenopus egg extracts after incubation, as 200 nm membrane vesicles attach to 10 nm filaments. These membrane vesicles fuse together along the filaments to form annulate lamellae (AL) or attach to demembranated sperm chromatin to initiate assembly of a nuclear envelope. Immunoassay with anti-keratin antibodies AE3 showed that the filaments were mainly composed of a 56 kDa keratin-like protein. Addition of AE3 to the extracts resulted in inhibition of AL formation and defective assembly of NE. These results suggest a function of keratins in the assembly of nuclear envelopes during Xenopus development.z 1998 Federation of European Biochemical Societies.

Maturation of Three Kinds of Keratin Networks in the Absorptive Cells of Rabbit Duodenum

“…Keratin filaments interact with the intracellular membrane system [6,44]. Actin filaments also bind to the membrane of the Golgi apparatus through various actinassociated proteins [31,39,41].…”

Seven Kinds of Intermediate Filament Networks in the Cytoplasm of Polarized Cells: Structure and Function

“…Keratin filaments interact directly or indirectly with the intracellular membrane system [20, 149]. Actin filaments also bind to the membrane of the Golgi apparatus through various actin-associated proteins [94, 125, 142].…”

“…The possibility that the radial network and juxtanuclear network are a part of that system should be considered for the following three reasons. First, the cytoplasmic IFs have a high binding affinity to both the plasma membrane [3, 17, 20, 45] and nuclear envelope [45, 92, 149]. In addition, the cytoplasmic IFs are connected to the nuclear IF network, the nuclear lamina, through the KASH protein in the outer nuclear membrane and the SUN protein in the inner nuclear membrane [123, 124].…”

Transient expression of keratin during neuronal development in the adult rabbit spinal ganglion

“…The components of this network may change into other intermediate filament proteins such as NF-M and NF-H with maturity of the neurons. Keratin filaments (Chou et al 1994;Zhang et al 1998) and neurofilaments (Hirokawa and Takeda 1998;Toivola et al 2005) interact with the intracellular membrane system. Some intermediate filament-associated proteins that mediate interaction among some kinds of intermediate filaments have also been reported (Herrmann and Aebi 2000).…”