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Macropinocytosis is a conserved endocytic process where cells take up medium into micron-sized vesicles. InDictyostelium, macropinocytic cups form around domains of PIP3 in the plasma membrane and extend by actin polymerization. Using lattice light-sheet microscopy, we describe how cups originate, are supported by an F-actin scaffold and shaped by a ring of actin polymerization, created around PIP3 domains. How cups close is unknown. We find two ways: lip closure, where actin polymerization at the lip is re-directed inwards; and basal closure, where it stretches the cup, eventually causing membrane delamination and vesicle sealing. Cups grow as expanding waves of actin polymerization that travel across the cell surface, capturing new membrane. We propose that cups close when these waves stall. This ‘stalled wave’ hypothesis is tested through a conceptual model, where the interplay of forces from actin polymerization and membrane tension recreates many of our observations.

Engulfment of extracellular material by phagocytosis or macropinocytosis depends on the ability of cells to generate specialized cup-shaped protrusions. To effectively capture and internalize their targets, these cups are organized into a ring or ruffle of actin-driven protrusion encircling a non-protrusive interior domain. These functional domains depend on the combined activities of multiple Ras and Rho family small GTPases, but how their activities are integrated and differentially regulated over space and time is unknown. Here, we show that the amoeba Dictyostelium discoideum coordinates Ras and Rac activity using the multidomain protein RGBARG (RCC1, RhoGEF, BAR, and RasGAP-containing protein). We find RGBARG uses a tripartite mechanism of Ras, Rac, and phospholipid interactions to localize at the protruding edge and interface with the interior of both macropinocytic and phagocytic cups. There, we propose RGBARG shapes the protrusion by expanding Rac activation at the rim while suppressing expansion of the active Ras interior domain. Consequently, cells lacking RGBARG form enlarged, flat interior domains unable to generate large macropinosomes. During phagocytosis, we find that disruption of RGBARG causes a geometry-specific defect in engulfing rod-shaped bacteria and ellipsoidal beads. This demonstrates the importance of coordinating small GTPase activities during engulfment of more complex shapes and thus the full physiological range of microbes, and how this is achieved in a model professional phagocyte.

Congenital muscular dystrophies display a wide phenotypic and genetic heterogeneity. The combination of clinical, biochemical, and molecular genetic findings must be considered to obtain the precise diagnosis and provide appropriate genetic counselling. Here we report five individuals from four families presenting with variable clinical features including muscular dystrophy with a reduction in dystroglycan glycosylation, short stature, intellectual disability, and cataracts, overlapping both the dystroglycanopathies and Marinesco-Sjogren syndrome. Whole-exome sequencing revealed homozygous missense and compound heterozygous mutations in INPP5K in the affected members of each family. INPP5K encodes the inositol polyphosphate-5-phosphatase K, also known as SKIP (skeletal muscle and kidney enriched inositol phosphatase), which is highly expressed in the brain and muscle. INPP5K localizes to both the endoplasmic reticulum and to actin ruffles in the cytoplasm. It has been shown to regulate myoblast differentiation and has also been implicated in protein processing through its interaction with the ER chaperone HSPA5/BiP. We show that morpholino-mediated inpp5k loss of function in the zebrafish results in shortened body axis, microphthalmia with disorganized lens, microcephaly, reduced touch-evoked motility, and highly disorganized myofibers. Altogether these data demonstrate that mutations in INPP5K cause a congenital muscular dystrophy syndrome with short stature, cataracts, and intellectual disability.

OPMS XXI allows for the career progression of the Army's functional specialists. It facilitates the development of commissioned officer functional specialists to fill critical positions at the Major, LTC, and Colonel levels. This study argues that OPMS XXI needs to be revised. It argues that the current MI officer career development as a part of the Operations Career Field (CF) falls short of developing the intelligence expertise required of intelligence staff officers (S2/G2) at the tactical level. It fails to develop officers capable of confidently exercising the skills required to integrate at the tactical level all of the elements embedded in the Intelligence cycle---the planning and directing of IEW operations; IEW collection operations; the processing of information and data; the production of intelligence; and the dissemination of this intelligence. It argues that the Army needs to develop tactical military intelligence officers that specialize in the application of intelligence for a military based on force projection and capable of operating across the entire spectrum of conflict. Specifically, tactical military operations in the 21st century will require a much greater level of specialized expertise within the intelligence career field, and that assessment and specialized development of intelligence staff officers (S2/G2) should begin at the time of promotion to the grade of captain and attendance to the advance course. It will suggest a career model for military intelligence officers that may be applicable to other functional areas as well.

This paper examines a process that has been in use by the U.S. Army at the tactical level of war for 15 years. It is a process that systematically analyzes the weather, terrain and the enemy in order to effectively predict an enemy's likely course of action. The products of this process are used by the tactical commander to identify the best possible friendly course of action in order to achieve the assigned tactical objectives... The process is known as Intelligence Preparation of the Battlefield (IPB). This paper will address why we use intelligence processes, briefly describe the IPB methodology, how it is applied at the tactical level of war, and how it can and should be applied at today's operational level of war. Intelligence Processing and Collection, Enemy and Battlefield Environment, and Synchronization.