Lapart, J.-A. | bioRxiv Science

bioRxiv2023

Alstrom syndrome proteins are novel regulators of centriolar cartwheel assembly and centrosome homeostasis in Drosophila

Centrioles play a central role in cell division by recruiting pericentriolar material (PCM) to form the centrosome. Alterations in centriole number or function lead to various diseases including cancer or microcephaly. Centriole duplication is a highly conserved mechanism in eukaryotes. Here, we show that the two Drosophila orthologs of the Alstrom syndrome protein 1 (Alms1a and Alms1b) are unexpected novel players of centriole duplication in fly. Using Ultrastructure Expansion Microscopy, we reveal that Alms1a is a PCM protein that is loaded proximally on centrioles at the onset of procentriole formation whereas Alms1b caps the base of mature centrioles. We demonstrate that chronic loss of Alms1 proteins affects PCM maturation, whereas their acute loss completely disrupts procentriole formation before Sas-6 cartwheel assembly. We establish that Alms1 proteins are required for the amplification of the Plk4-Ana2 pool at the duplication site and the subsequent Sas-6 recruitment. Thus, Alms1 proteins are novel critical but highly buffered regulators of PCM and cartwheel assembly in flies.

cell biology↗

bioRxiv2023

EASYSTIFF(R), a portable and innovative device able to separately analyze each skin compartment for the evaluation of mechanical properties.

Human skin is submitted to various factors leading to either extrinsic or intrinsic aging. In addition to inducing molecular and morphological changes, skin aging is characterized by modifications in skin biomechanical properties modifications. These modifications can be used as biomarkers to both evaluate the degree of advancement in skin aging but also to detect potential pathologies. Hence, it is from critical interest to be able to evaluate skin biomechanical properties to fully detect and monitor these alterations. Here we introduce a portable and innovative (R)device, EASYSTIFF(R), which is thought to in vivo measure stiffness properties of skin. Based on indentation principle, EASYSTIFF allows to identify both global stiffness of skin (all confounded cutaneous compartment) or compartmentalized stiffness, in which stiffness values of each compartment, i.e., the stratum corneum, the epidermis, the dermis and the hypodermis, are separately analyzed. Thus, EASYSTIFF is a complementary tool to 2D and 3D in/ex vivo model and an alternative to existing devices that measure skin mechanical properties, for assessing the effectiveness of cosmetic products, monitoring skin stiffness over time and to provide better understanding in the evolution of skin mechanical properties.

biophysics↗