Control of topology and mode of assembly of a polytopic membrane protein by positively charged residues

Nature ◽  
1989 ◽  
Vol 341 (6241) ◽  
pp. 456-458 ◽  
Author(s):  
Gunnar vonHeijne
Keyword(s):  
Membrane Protein ◽  
Charged Residues ◽  
Polytopic Membrane Protein ◽  
Positively Charged

scholarly journals ANKRD22 is an N-myristoylated hairpin-like monotopic membrane protein specifically localized to lipid droplets

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Toshihiko Utsumi ◽  
Takuro Hosokawa ◽  
Mayu Shichita ◽  
Misato Nishiue ◽  
Natsuko Iwamoto ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Lipid Droplets ◽  
Transmembrane Domain ◽  
Intracellular Localization ◽  
Membrane Topology ◽  
Intracellular Targeting ◽  
C Terminus ◽  
Charged Residues ◽  
Necrosis Factor ◽  
Positively Charged

AbstractThe membrane topology and intracellular localization of ANKRD22, a novel human N-myristoylated protein with a predicted single-pass transmembrane domain that was recently reported to be overexpressed in cancer, were examined. Immunofluorescence staining of COS-1 cells transfected with cDNA encoding ANKRD22 coupled with organelle markers revealed that ANKRD22 localized specifically to lipid droplets (LD). Analysis of the intracellular localization of ANKRD22 mutants C-terminally fused to glycosylatable tumor necrosis factor (GLCTNF) and assessment of their susceptibility to protein N-glycosylation revealed that ANKRD22 is synthesized on the endoplasmic reticulum (ER) membrane as an N-myristoylated hairpin-like monotopic membrane protein with the amino- and carboxyl termini facing the cytoplasm and then sorted to LD. Pro98 located at the center of the predicted membrane domain was found to be essential for the formation of the hairpin-like monotopic topology of ANKRD22. Moreover, the hairpin-like monotopic topology, and positively charged residues located near the C-terminus were demonstrated to be required for the sorting of ANKRD22 from ER to LD. Protein N-myristoylation was found to positively affect the LD localization. Thus, multiple factors, including hairpin-like monotopic membrane topology, C-terminal positively charged residues, and protein N-myristoylation cooperatively affected the intracellular targeting of ANKRD22 to LD.

Estimating Loop−Helix Interfaces in a Polytopic Membrane Protein by Deletion Analysis†

Biochemistry ◽  
1999 ◽  
Vol 38 (26) ◽  
pp. 8590-8597 ◽  
Author(s):  
Christopher D. Wolin ◽  
H. Ronald Kaback
Keyword(s):  
Membrane Protein ◽  
Deletion Analysis ◽  
Polytopic Membrane Protein

scholarly journals Clusters of Charged Residues at the C Terminus of MotA and N Terminus of MotB Are Important for Function of the Escherichia coli Flagellar Motor

2008 ◽  
Vol 190 (15) ◽  
pp. 5517-5521 ◽  
Author(s):  
Edan R. Hosking ◽  
Michael D. Manson
Keyword(s):  
Escherichia Coli ◽  
Flagellar Motor ◽  
Protein Levels ◽  
Partner Protein ◽  
C Terminus ◽  
N Terminus ◽  
Charged Residues ◽  
Positively Charged ◽  
Terminal Cluster

ABSTRACT MotA contains a conserved C-terminal cluster of negatively charged residues, and MotB contains a conserved N-terminal cluster of positively charged residues. Charge-altering mutations affecting these residues impair motility but do not diminish Mot protein levels. The motility defects are reversed by second-site mutations targeting the same or partner protein.

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