FB2026_03 , released September 17, 2026
Physical Interaction report
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General Information
Interaction Type
Interacting Genes
FlyBase ID
FBig0000108251
Interaction Network
Interactions Browser links
osk network
smg network
Reported Interactions
FBrf0212721-10.PD.A
Description
physical association
Collection
Source/Stage
Cell line used
Participants
Corresponds to
Reported as
Role
Note
osk 

Osk

bait

GST tag

smg 

smaug

prey

[35]S label

Experimental entities
Corresponds to
Identifier
Reported
Role
Note
Subregions with role in interaction
Corresponds to
Description
Role
Coordinates
Note
Isoform-specific participants
Corresponds to
Description
Role
Note
Comments concerning this interaction

Interaction in vitro; bait produced as a recombinant fusion protein in bacterial system; prey produced and labeled by in vitro translation.

FBrf0257154-10.PD.MW
Description
physical association
Collection
Source/Stage
Cell line used
Participants
Corresponds to
Reported as
Role
Note
osk 

Smo

bait

MBP tag

osk 
smg 

Smaug

prey

His tag (removed)

smg 
Experimental entities
Corresponds to
Identifier
Reported
Role
Note
Subregions with role in interaction
Corresponds to
Description
Role
Coordinates
Note
osk 
smg binding region residues 292-325
necessary binding region
aa 292-325
smg 
NTD residues 37-281
sufficient binding region
aa 250 and 253
Isoform-specific participants
Corresponds to
Description
Role
Note
Comments concerning this interaction

Interaction in vitro; bait and prey produced as recombinant fusion proteins in bacterial system.

FBrf0257154-11.PD.MW
Description
physical association
Collection
Source/Stage
Cell line used
Participants
Corresponds to
Reported as
Role
Note
smg 

Smaug

bait

GST tag

smg 
osk 

Oskar

prey

MBP tag

Experimental entities
Corresponds to
Identifier
Reported
Role
Note
Subregions with role in interaction
Corresponds to
Description
Role
Coordinates
Note
smg 
NTD residues 1-281
sufficient binding region
aa 1-281
Isoform-specific participants
Corresponds to
Description
Role
Note
Comments concerning this interaction

Addition of smo synthetic Smaug binding region peptide competed with smg-osk interaction, however mutated smo peptide containing L978E/L984E/L985 did not.

Interaction in vitro; bait and prey produced as recombinant fusion proteins in bacterial system.

FBrf0257154-12.CL.FM
Description
physical association
Collection
Source/Stage
Cell line used
Participants
Corresponds to
Reported as
Role
Note
osk 

Oskar

bait

OST4-EGFP fused to ER membrane anchor

osk 
smg 

Smaug

prey

mCherry tag

smg 
Experimental entities
Corresponds to
Identifier
Reported
Role
Note
Subregions with role in interaction
Corresponds to
Description
Role
Coordinates
Note
osk 
smg binding domain residues 295-352
necessary binding region
aa 295-352
smg 
NTD domain residues 250 and 253
necessary binding region
aa 250 and 253

S250E, L253E

Isoform-specific participants
Corresponds to
Description
Role
Note
Comments concerning this interaction

Source was S2R+ cells; bait and prey produced from transfected construct.

Bait protein was fused to ER membrane anchor. The ability of this chimera to recruit prey protein to the ER was taken as evidence of direct physical interaction.

FBrf0257154-7.CL.FM
Description
physical association
Collection
Source/Stage
Cell line used
Participants
Corresponds to
Reported as
Role
Note
osk 

Oskar

bait

OST4-mCherry fused to ER membrane anchor

smg 

Smaug

prey

EGFP tag

Experimental entities
Corresponds to
Identifier
Reported
Role
Note
Subregions with role in interaction
Corresponds to
Description
Role
Coordinates
Note
Isoform-specific participants
Corresponds to
Description
Role
Note
Comments concerning this interaction

Source was S2R+ cells; bait and prey produced from transfected construct.

Bait protein was fused to ER membrane anchor. The ability of this chimera to recruit prey protein to the ER was taken as evidence of direct physical interaction. osk-PC short isoform (139-

606) interacts with smg but does not interact with the PA isoform (long).

FBrf0257154-9.Y2H
Description
physical association
Assay
Collection
Source/Stage
Cell line used
Participants
Corresponds to
Reported as
Role
Note
osk 

Oskar

bait

fused to C-ub

osk 
smg 

Smaug

prey

fused to N-ub

smg 
Experimental entities
Corresponds to
Identifier
Reported
Role
Note
Subregions with role in interaction
Corresponds to
Description
Role
Coordinates
Note
osk 
smg binding domain residues 292-306
necessary binding region
aa 292-306
smg 
NTD domain residues aa 1-281
sufficient binding region
aa 1-281
Isoform-specific participants
Corresponds to
Description
Role
Note
Comments concerning this interaction

Split ubiquitin Y2H

Source was yeast cell line; bait produced as transgenic fusion protein; prey produced as transgenic fusion protein (prey was previously cloned reagent).

External Crossreferences and Linkouts ( 1 )
Linkouts
MIST - An integrated Molecular Interaction Database
References (2)