FIP-2, an IkappaB-kinase-gamma-related protein, is associated with the Golgi apparatus and translocates to the marginal band during chicken erythroblast differentiation.
Using an antiserum directed against marginal band associated proteins of chicken erythrocytes we isolated clones encoding the chicken homolog of 14.7K-interacting protein 2 (FIP-2), a protein potentially involved in tumor necrosis factor-alpha/nuclear factor-kappaB signaling, from a chicken erythroblast cDNA library. We found that chicken FIP-2 was expressed in a variety of tissues and cell types, but unlike its human counterpart, alternative splicing does not appear to take place. Analysis of intracellular localization revealed that FIP-2 was concentrated at the Golgi apparatus in most cells. Perturbation of the Golgi structure without loss of Golgi function (by treatment with nocodazole) resulted in a retention of FIP-2 at the dispersed Golgi fragments. In contrast, disruption of both Golgi structure and function (by brefeldin A) led to a loss of FIP-2 from Golgi membranes. Remarkably, during erythroblast differentiation FIP-2 was found to translocate from the Golgi to the marginal band. Our results support the hypothesis of a function of the Golgi apparatus in signal transduction. Moreover, our results raise the possibility that the marginal band of chicken erythrocytes, in addition to its role in morphogenesis, has a function in signal transduction and that FIP-2 is in some way involved in its formation.
Stroissnigg
Heike
H
Institute of Biochemistry and Molecular Cell Biology, Vienna Biocenter, University of Vienna, Dr. Bohr-Gasse 9, A-1030 Vienna, Austria.
Repitz
Marion
M
Miloloza
Angelina
A
Linhartova
Irena
I
Beug
Hartmut
H
Wiche
Gerhard
G
Propst
Friedrich
F
D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism* / Q000502:physiology; D002454:Cell Differentiation; D002645:Chickens; D004900:Erythroblasts / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism*; D006056:Golgi Apparatus / Q000378:metabolism* / Q000502:physiology; D051550:I-kappa B Kinase; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000378:metabolism* / Q000502:physiology; D008969:Molecular Sequence Data; D017346:Protein Serine-Threonine Kinases; D021381:Protein Transport; D016415:Sequence Alignment; D015398:Signal Transduction
D002352:Carrier Proteins; D017346:Protein Serine-Threonine Kinases; D051550:I-kappa B Kinase