Attending to remember and remembering to attend

Attention and memory are intimately linked. Two functional imaging studies in this issue of Neuron provide novel evidence for this powerful, reciprocal relationship. Turk-Browne and colleagues report that attention simultaneously facilitates the formation of both implicit and explicit memories, while Summerfield and colleagues demonstrate that memory for the past can guide the allocation of attention in the present. Together, these elegant studies reveal bidirectional interactions between attention and memory.     

Diverse mechanisms to remember various odors

Two dorsal paired medial (DPM) neurons express the Amnesiac neuropeptide and project onto mushroom bodies, the Drosophila olfactory memory center. In this issue of Neuron, Keene et al. show that higher-level brain circuits process various olfactory memories differently. DPM neurons are required during acquisition of some odors and during memory consolidation of others. These findings reveal a surprising level of complexity for the formation of olfactory memories in Drosophila.     

Apoer2: a reelin receptor to remember

The extracellular protein Reelin is crucial for neuronal positioning during brain development, but its expression persists long after cell migration is completed. In this issue of Neuron, Beffert et al. demonstrate that Reelin exerts an additional function in the mature brain, to modulate synaptic plasticity and to favor memory formation. This activity is carried out exquisitely by the Apoer2 receptor and critically requires the presence of an alternatively spliced exon. This exon encodes an intracellular domain that interacts with postsynaptic proteins and promotes binding and phosphorylation of NMDA receptors.     

We remember Eugene

This article is written in memory of Eugene Rabinowitch, one of the major prophets of photosynthesis. I speak on behalf of all the students and post-doctorial associates who were fortunate to be associated with and to have loved this wonderful man. I shall also describe my research with Eugene. We all remember him on the 1995 anniversary of his death (May 15, 1973).Written at the invitation of Govindjee.     

Mitosis--From Molecules to Machine

This paper concerns the mechanism of mitosis. I briefly reviewthe history of mitosis research, emphasizing the role of microscopicobservation. The polymerization and depolymerization of microtubulesplay central roles in both the assembly of the spindle, andin the way it moves chromosomes. I describe recent advancesin understanding the dynamic behavior of individual microtubules,and of microtubules attached to kinetochores. The kinetochoreis able to hold on to microtubule ends while allowing them togrow and shrink, reactions that can be studied both in livingcells and in the test tube. Experiments in which microtubulesin living cells are marked and then followed allow us to relatethese individual dynamic processes to the overall mechanismof chromosome movement. I end the review by speculating aboutbiochemical mechanisms for producing force on chromosomes inanaphase, and for balancing chromosomes in the center of themetaphase spindle.     

Peroxide-Induced Damage to Plasminogen Molecules

Doklady Biochemistry and Biophysics - Plasminogen is a zymogenic form of plasmin, an enzyme that plays a fundamental role in the dissolution of fibrin clots as well as in many other physiological...     

Learning to remember: generation and maintenance of T-cell memory

Immunologic memory results from a carefully coordinated interplay between cells of the immune system. In this review, we explore various aspects of the nature, generation, and maintenance of T lymphocyte-mediated immunologic memory. In light of the demonstrated heterogeneity of the memory T-cell pool, we hypothesize that subsets of memory T cells instructed to mature to distinct differentiation stages may differ, not only in functional and homing properties, but also in the conditions they require for survival, including antigen persistence and cytokine environment. Hence, according to this hypothesis, distinct memory T-cell subsets result from the nature and timing of the signals provided by the immune environment and occupy distinct niches. Intracellular and extracellular molecular mechanisms that underlie and modulate T-cell memory are discussed.     

Mechano-Transduction: From Molecules to Tissues

External forces play complex roles in cell organization, fate, and homeostasis. Changes in these forces, or how cells respond to them, can result in abnormal embryonic development and diseases in adults. How cells sense and respond to these mechanical stimuli requires an understanding of the biophysical principles that underlie changes in protein conformation and result in alterations in the organization and function of cells and tissues. Here, we discuss mechano-transduction as it applies to protein conformation, cellular organization, and multi-cell (tissue) function.     

Stem cells remember their grade

The stem cell state is understood based on what cells do in performance assays, crude measures of a highly refined state. In this issue of Cell Stem Cell, Dykstra et al. (2007) reveal stem cell gradation and the extent to which that gradation is retained in stem cell daughters of hematopoietic stem cells.