The Sema3A receptor Plexin-A1 suppresses supernumerary axons through Rap1 GTPases.

The highly conserved Rap1 GTPases perform essential functions during neuronal development. They are required for the polarity of neuronal progenitors and neurons as well as for neuronal migration in the embryonic brain. Neuronal polarization and axon formation depend on the precise temporal and spatial regulation of Rap1 activity by guanine nucleotide exchange factors (GEFs) and GTPases-activating proteins (GAPs).

The loss of the kinases SadA and SadB results in early neuronal apoptosis and a reduced number of progenitors.

The neurons that form the mammalian neocortex originate from progenitor cells in the ventricular (VZ) and subventricular zone (SVZ). Newborn neurons are multipolar but become bipolar during their migration from the germinal layers to the cortical plate (CP) by forming a leading process and an axon that extends in the intermediate zone (IZ). Once they settle in the CP, neurons assume a highly polarized morphology with a single axon and multiple dendrites.

High-resolution Imaging in Male Germ Cell-Associated Kinase (MAK)-related Retinal Degeneration.

Purpose: To describe the characteristics of MAK-related retinal degeneration using optical coherence tomography angiography (OCTA) and adaptive optics scanning laser ophthalmoscopy (AOSLO).

Design: Cross-sectional study.

Methods: Six patients with rod-cone degeneration and disease-causing mutations in MAK were evaluated with visual acuity, spectral-domain OCT, confocal AOSLO, and OCTA.