High impact information on Apba1

• The MALS/Veli-CASK-Mint-1 complex of PDZ proteins occurs on both sides of the synapse and has the potential to link transsynaptic adhesion molecules to the cytoskeleton [1].
• Our data indicate that Mints 1 and 2 perform redundant synaptic functions that become apparent in Mint 1-deficient mice in inhibitory interneurons because these neurons selectively express higher levels of Mint 1 than Mint 2 [2].
• We find that Mints 1 and 2 are similarly expressed in most neurons except for inhibitory interneurons that contain selectively high levels of Mint 1 [2].
• In electrophysiological recordings in the hippocampus, we observed no changes in short- or long-term synaptic plasticity in excitatory synapses from Mint 1-deficient mice and detected no alterations in the ratio of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) to N-methyl-d-aspartate (NMDA) receptor-mediated synaptic currents [2].
• Thus the Mint 1-CASK complex is not required for AMPA- and NMDA-receptor functions or for synaptic plasticity in excitatory synapses [2].

Biological context of Apba1

• A role for Mints in transmitter release: Mint 1 knockout mice exhibit impaired GABAergic synaptic transmission [2].
• Mint-1, which is also called as X11 or mammalian Lin10, protein has been implicated in the synaptic vesicle exocytosis and the targeting and localization of synaptic membrane proteins [3].
• Hippocampal slice electrophysiology uncovered a decline in spontaneous neurotransmitter release, lowered synaptic strength, and enhanced paired-pulse facilitation in Mint-deficient mice, suggesting a decreased presynaptic release probability [4].
• Four such integration sites, designated as Mint (for Moloney murine leukemia virus integration and expression sites in EC cells), have been mapped on mouse chromosomes [5].

Anatomical context of Apba1

• In Caenorhabditis elegans, three PDZ domain proteins, Lin-2, Lin-7, and Lin-10, are necessary for the proper targeting of the Let-23 growth factor receptor to the basolateral surface of epithelial cells [6].
• Mint1 intensely stained catecholamine-containing neurons such as the substantia nigra pars compacta, ventral tegmental area, and locus ceruleus [7].
• Mint1 mRNA expression was greatest in the limbic system including cingulate cortex, hippocampus, anterior thalamic nuclei, medial habenular nucleus, and mammillary body [7].
• Mint1, a neuronal isoform, is involved in synaptic vesicle exocytosis [8].
• Mint1 distribution within presynaptic terminals overlapped that of munc18-1 [9].

Associations of Apba1 with chemical compounds

• In inhibitory synapses, however, we uncovered an approximately 3-fold increase in presynaptic paired-pulse depression, suggesting that deletion of Mint 1 impairs the regulation of gamma-aminobutyric acid release [2].

Physical interactions of Apba1

• Here, we report that X11alpha directly binds to the mammalian homologue of Lin-2 (mLin-2), also known as CASK [10].

Other interactions of Apba1

• This binding is mediated by direct interaction between the Calmodulin Kinase II (CKII)-like domain of mLin-2 and the amino terminus of X11alpha [10].
• In mouse brain, we have identified a heterotrimeric complex that contains mLin-2, mLin-7, and X11alpha and that is likely important for the localization of proteins in polarized cells [10].
• Mint1, but not Mint2 mRNA was abundant in the substantia nigra pars compacta [7].

References