Membrane-Binding Amphipathic .alpha.-Helical Peptide Derived from CTP:Phosphocholine Cytidylyltransferase

Biochemistry ◽  
1994 ◽  
Vol 33 (14) ◽  
pp. 4327-4335 ◽  
Author(s):  
Joanne E. Johnson ◽  
Rosemary B. Cornell
Keyword(s):  
Membrane Binding ◽  
Ctp:Phosphocholine Cytidylyltransferase ◽  
Helical Peptide ◽  
Alpha Helical Peptide

scholarly journals The Rate-limiting Enzyme in Phosphatidylcholine Synthesis Regulates Proliferation of the Nucleoplasmic Reticulum

2005 ◽  
Vol 16 (3) ◽  
pp. 1120-1130 ◽  
Author(s):  
Thomas A. Lagace ◽  
Neale D. Ridgway
Keyword(s):  
Membrane Binding ◽  
Chinese Hamster ◽  
Lipid Synthesis ◽  
Temperature Sensitive ◽  
Direct Role ◽  
Tubule Formation ◽  
Ctp:Phosphocholine Cytidylyltransferase ◽  
Nucleoplasmic Reticulum ◽  
Rate Limiting

The nucleus contains a network of tubular invaginations of the nuclear envelope (NE), termed the nucleoplasmic reticulum (NR), implicated in transport, gene expression, and calcium homeostasis. Here, we show that proliferation of the NR, measured by the frequency of NE invaginations and tubules, is regulated by CTP:phosphocholine cytidylyltransferase-α (CCTα), the nuclear and rate-limiting enzyme in the CDP–choline pathway for phosphatidylcholine (PtdCho) synthesis. In Chinese hamster ovary (CHO)-K1 cells, fatty acids triggered activation and translocation of CCTα onto intranuclear tubules characteristic of the NR. This was accompanied by a twofold increase in NR tubules quantified by immunostaining for lamin A/C or the NE. CHO MT58 cells expressing a temperature-sensitive CCTα allele displayed reduced PtdCho synthesis and CCTα expression and minimal proliferation of the NR in response to oleate compared with CHO MT58 cells stably expressing CCTα. Expression of CCTα mutants in CHO58 cells revealed that both enzyme activity and membrane binding promoted NR proliferation. In support of a direct role for membrane binding in NR tubule formation, recombinant CCTα caused the deformation of liposomes into tubules in vitro. This demonstrates that a key nuclear enzyme in PtdCho synthesis coordinates lipid synthesis and membrane deformation to promote formation of a dynamic nuclear-cytoplasmic interface.

Structural characteristics of .alpha.-helical peptide molecules containing Aib residues

Biochemistry ◽  
1990 ◽  
Vol 29 (29) ◽  
pp. 6747-6756 ◽  
Author(s):  
Isabella L. Karle ◽  
Padmanabhan Balaram
Keyword(s):  
Structural Characteristics ◽  
Helical Peptide ◽  
Alpha Helical Peptide
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