Dependence of calmodulin localization in the retina on the NINAC unconventional myosin.

  title={Dependence of calmodulin localization in the retina on the NINAC unconventional myosin.},
  author={Jeffery A. Porter and M M Yu and Stephen. Doberstein and T D Pollard and Craig Montell},
  volume={262 5136},
Calmodulin is a highly conserved regulatory protein found in all eukaryotic organisms which mediates a variety of calcium ion-dependent signalling pathways. In the Drosophila retina, calmodulin was concentrated in the photoreceptor cell microvillar structure, the rhabdomere, and was found in lower amounts in the sub-rhabdomeral cytoplasm. This calmodulin localization was dependent on the NINAC (neither inactivation nor afterpotential C) unconventional myosins. Mutant flies lacking the… 

Calmodulin binding to Drosophila NinaC required for termination of phototransduction.

Evidence is presented for two calmodulin‐binding sites in NinaC, C1 and C2, which have different in vitro binding properties and which suggest that cal modulin binding to both C2 and C1 is required in vivo for termination of phototransduction.

Role of the ninaC proteins in photoreceptor cell structure: ultrastructure of ninaC deletion mutants and binding to actin filaments.

Structural roles for the ninaC proteins are outlined, and are consistent with the notion, suggested by their amino acid sequences, that the proteins are actin-based mechanoenzymes.

Requirement for the NINAC Kinase/Myosin for Stable Termination of the Visual Cascade

It is shown that NINAC p174, which consists of a protein kinase domain joined to the head region of myosin heavy chain, is a phosphoprotein and is phosphorylated in vitro by PKC and that p174 participates in this process.

Retinal Targets for Calmodulin Include Proteins Implicated in Synaptic Transmission*

Calmodulin appears to functions as a Ca2+ sensor for a broad diversity of retinal proteins, some of which are implicated in synaptic transmission.

Dependence on a Retinophilin/Myosin Complex for Stability of PKC and INAD and Termination of Phototransduction

It is concluded that the slower termination of the photoresponse in retin1 resulted from a requirement for the Retin/NINAC complex for stability of INAD and PKC.

A Myosin III from Limulus Eyes Is a Clock-Regulated Phosphoprotein

It is proposed that the phosphorylation of Limulus myosin III is involved in one or more of the structural and functional changes that occur in Limulus eyes in response to clock input.

Interactions of Calmodulin and α-Actinin with the NR1 Subunit Modulate Ca2+-Dependent Inactivation of NMDA Receptors

It is proposed that inactivation can occur after C0 dissociates from α-actinin by two distinct but converging calcium-dependent processes: competitive displacement ofα-act inin by calmodulin and reduction in the affinity of α-Actinin for C0 after binding of calcium to α- actinin.

Termination of phototransduction requires binding of the NINAC myosin III and the PDZ protein INAD

It is demonstrated that INAD bound directly to the NINac myosin III, yet the subcellular localization of NINAC was normal in inaD mutants, and the INAD binding site was sufficient to target a heterologous protein to the rhabdomeres.



Differential localizations of and requirements for the two Drosophila ninaC kinase/myosins in photoreceptor cells

It is demonstrated that the ninaC mutation results in light- and age-dependent retinal degeneration, and it is shown that nINAC flies display an electrophysiological phenotype before any discernible retina degeneration indicating that the electrophYSiological defect is the primary effect of the mutation.

Association of calmodulin and an unconventional myosin with the contractile vacuole complex of Dictyostelium discoideum

Results suggest that a calmodulin-binding unconventional myosin is associated with contractile vacuoles in Dictyostelium; similar proteins in yeast and mammalian cells have been implicated in vesicle movement.

Gene encoding cytoskeletal proteins in Drosophila rhabdomeres.

Ulastructural studies show that the polypeptides encoded by ninaC are very likely to be important components of the cytoskeletal structure of rhabdomeral microvilli.

Calmodulin and calmodulin binding proteins in amphibian rod outer segments.

The calmodulin (CaM) content of fully intact frog rod outer segments (ROS) has been measured. The molar ratio between rhodopsin and total CaM in ROS is 800:1. This is in good agreement with the data

Distinct roles of the Drosophila ninaC kinase and myosin domains revealed by systematic mutagenesis

The results indicated that the ERG and retinal degeneration phenotypes were not strictly coupled suggesting that the myosin domain has multiple functions, and it is proposed that the role of the kinase domain is to regulate other rhabdomeric proteins important in phototransduction.

Calmodulin concentrates at regions of cell growth in Saccharomyces cerevisiae

Calmodulin was localized in Saccharomyces cerevisiae by indirect immunofluorescence using affinity-purified polyclonal antibodies and indicates that calmodulin and actin concentrate in overlapping regions during the cell cycle.

Identification of actin filaments in the rhabdomeral microvilli of Drosophila photoreceptors

The present study shows that actin filaments are a component of this cytoskeleton in Drosophila, and provides an indication as to how any myosin that is associated with the rhabdomeres might function.