Distinct and redundant functions of mu1 medium chains of the AP-1 clathrin-associated protein complex in the nematode Caenorhabditis elegans.
In the nematode Caenorhabditis elegans, there exist two micro1 medium chains of the AP-1 clathrin-associated protein complex. Mutations of unc-101, the gene that encodes one of the micro1 chains, cause pleiotropic effects (). In this report, we identified and analyzed the second mu1 chain gene, apm-1. Unlike the mammalian homologs, the two medium chains are expressed ubiquitously throughout development. RNA interference (RNAi) experiments with apm-1 showed that apm-1 and unc-101 were redundant in embryogenesis and in vulval development. Consistent with this, a hybrid protein containing APM-1, when overexpressed, rescued the phenotype of an unc-101 mutant. However, single disruptions of apm-1 or unc-101 have distinct phenotypes, indicating that the two medium chains may have distinct functions. RNAi of any one of the small or large chains of AP-1 complex (sigma1, beta1, or gamma) showed a phenotype identical to that caused by the simultaneous disruption of unc-101 and apm-1, but not that by single disruption of either gene. This suggests that the two medium chains may share large and small chains in the AP-1 complexes. Thus, apm-1 and unc-101 encode two highly related micro1 chains that share redundant and distinct functions within AP-1 clathrin-associated protein complexes of the same tissue.
Department of Biology, Yonsei University, Seoul, Korea.
J
J
Shim
P W
PW
Sternberg
J
J
Lee
D033961:Adaptor Protein Complex 1; D033962:Adaptor Protein Complex 2; D033965:Adaptor Protein Complex alpha Subunits; D033983:Adaptor Protein Complex mu Subunits; D034002:Adaptor Protein Complex sigma Subunits; D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000187:drug effects / Q000196:embryology / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins; D002966:Clathrin / Q000502:physiology*; D003001:Cloning, Molecular; D004625:Embryo, Nonmammalian / Q000502:physiology; D019143:Evolution, Molecular; D005260:Female; D018507:Gene Expression Regulation, Developmental; D015801:Helminth Proteins / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D007814:Larva / Q000502:physiology; D008565:Membrane Proteins / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000187:drug effects / Q000235:genetics* / Q000502:physiology*; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D010641:Phenotype; D010750:Phosphoproteins / Q000187:drug effects / Q000235:genetics* / Q000502:physiology*; D012330:RNA, Double-Stranded / Q000494:pharmacology; D018510:RNA, Helminth / Q000096:biosynthesis / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014844:Vulva / Q000166:cytology / Q000196:embryology / Q000378:metabolism
D033961:Adaptor Protein Complex 1; D033962:Adaptor Protein Complex 2; D033965:Adaptor Protein Complex alpha Subunits; D033983:Adaptor Protein Complex mu Subunits; D034002:Adaptor Protein Complex sigma Subunits; D033942:Adaptor Proteins, Vesicular Transport; D029742:Caenorhabditis elegans Proteins; D002966:Clathrin; D015801:Helminth Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D019384:Nucleic Acid Synthesis Inhibitors; D010750:Phosphoproteins; D012330:RNA, Double-Stranded; D018510:RNA, Helminth; D011993:Recombinant Fusion Proteins; C085440:UNC-101 protein, C elegans; C499066:adaptor protein complex 1, mu 1 subunit; C499071:adaptor protein complex 1, sigma 1 subunit; C438885:adaptor protein complex 2, mu 1 subunit; C499069:apm-1 protein, C elegans