High impact information on MACF1

• In endodermal cells, ACF7 binds along microtubules but concentrates at their distal ends and at cell borders when polarized [1].
• Here, we report on ACF7, a mammalian orthologue of the Drosophila kakapo plakin genetically involved in epidermal-muscle adhesion and neuromuscular junctions [2].
• In well spread epidermal keratinocytes, ACF7 discontinuously decorates the cytoskeleton at the cell periphery, including microtubules (MTs) and actin filaments (AFs) that are aligned in parallel converging at focal contacts [2].
• Treatments with cytoskeletal depolymerizing drugs reveal that ACF7's cytoskeletal association is dependent upon the microtubule network, but ACF7 also appears to stabilize actin at sites where microtubules and microfilaments meet [2].
• Upon calcium induction of intercellular adhesion, ACF7 and the cytoskeleton reorganize at cell-cell borders but with different kinetics from adherens junctions and desmosomes [2].

Biological context of MACF1

• The MACF1 gene is located on human Chr 1p32, contains at least 102 exons, spans over 270 kb, and gives rise to four major isoforms with different N-termini [3].
• By using the oligonucleotide-containing random 9mer together with the GC-rich sequence for the suppression PCR technology at the first strand of cDNA synthesis, we have been able to amplify the cDNA from a very large transcript, such as the microtubule-actin crosslinking factor 1 (MACF1) gene, which codes a transcript of 20 kb in size [4].
• In this report, we describe the characterization of this microtubule-binding domain of MACF by transient transfection studies and in vitro binding assays [5].
• The ACF7 gene is on human chromosome 1 and hybridizes to high molecular weight bands on northern blots [6].
• Mammalian MACF1 (Macrophin1; previously named ACF7) is a giant cytoskeletal linker protein with three known isoforms that arise by alternative splicing [3].

Anatomical context of MACF1

• Reducing the level of MACF1 proteins by small-interfering RNA resulted in the dispersal of the Golgi complex [7].
• We found that this domain interacts with the carboxyl-terminal domain of MACF1, a protein that cross-links microtubules to the actin cytoskeleton [8].
• High expression of macrophin was observed in brain, heart, lung, placenta, liver, kidney, and pancreas [9].
• In pancreas, we found that macrophin was specifically expressed in acinar cells than islet cells by in situ hybridization [9].
• We find that ACF7 regulates cortical CLASP localization in HeLa cells, indicating it acts upstream of CLASP2 [10].

Associations of MACF1 with chemical compounds

• Interaction between p230 and MACF1 is associated with transport of a glycosyl phosphatidyl inositol-anchored protein from the Golgi to the cell periphery [8].
• Star Ruby grapefruit (Citrus paradisi Macf.) were subjected to a 3-min dip in water at room temperature (20 degrees C) or at 50 degrees C with or without 25, 50, or 100 mg/L azoxystrobin (AZX) [11].
• Use of nootkatone as a senescence indicator for Rouge La Toma Cv. grapefruit (Citrus paradisi Macf.) [12].

Other interactions of MACF1

• The microtubule-binding properties of MACF2 C-terminal domain are similar to that of MACF [5].

Analytical, diagnostic and therapeutic context of MACF1

• Molecular cloning and characterization of human trabeculin-alpha, a giant protein defining a new family of actin-binding proteins [13].
• By using radiation hybrid panel, we have mapped the macrophin gene to the chromosome 1p31-32 [9].

References