Investigation of the Interaction between Cdc42 and Its Effector TOCA1: HANDOVER OF Cdc42 TO THE ACTIN REGULATOR N-WASP IS FACILITATED BY DIFFERENTIAL BINDING AFFINITIES.

Transducer of Cdc42-dependent actin assembly protein 1 (TOCA1) is an effector of the Rho family small G protein Cdc42. It contains a membrane-deforming F-BAR domain as well as a Src homology 3 (SH3) domain and a G protein-binding homology region 1 (HR1) domain. TOCA1 binding to Cdc42 leads to actin rearrangements, which are thought to be involved in processes such as endocytosis, filopodia formation, and cell migration. We have solved the structure of the HR1 domain of TOCA1, providing the first structural data for this protein. We have found that the TOCA1 HR1, like the closely related CIP4 HR1, has interesting structural features that are not observed in other HR1 domains. We have also investigated the binding of the TOCA HR1 domain to Cdc42 and the potential ternary complex between Cdc42 and the G protein-binding regions of TOCA1 and a member of the Wiskott-Aldrich syndrome protein family, N-WASP. TOCA1 binds Cdc42 with micromolar affinity, in contrast to the nanomolar affinity of the N-WASP G protein-binding region for Cdc42. NMR experiments show that the Cdc42-binding domain from N-WASP is able to displace TOCA1 HR1 from Cdc42, whereas the N-WASP domain but not the TOCA1 HR1 domain inhibits actin polymerization. This suggests that TOCA1 binding to Cdc42 is an early step in the Cdc42-dependent pathways that govern actin dynamics, and the differential binding affinities of the effectors facilitate a handover from TOCA1 to N-WASP, which can then drive recruitment of the actin-modifying machinery.

Alcohol-attributable deaths and years of potential life lost--11 States, 2006-2010.

Excessive alcohol consumption, the fourth leading preventable cause of death in the United States, resulted in approximately 88,000 deaths and 2.5 million years of potential life lost (YPLL) annually during 2006-2010 and cost an estimated $223.5 billion in 2006. To estimate state-specific average annual rates of alcohol-attributable deaths (AAD) and YPLL caused by excessive alcohol use, 11 states analyzed 2006-2010 data (the most recent data available) using the CDC Alcohol-Related Disease Impact (ARDI) application. The age-adjusted median AAD rate was 28.5 per 100,000 population (range = 50.9 per 100,000 in New Mexico to 22.4 per 100,000 in Utah). The median YPLL rate was 823 per 100,000 (range = 1,534 YPLL per 100,000 for New Mexico to 634 per 100,000 in Utah). The majority of AAD (median = 70%) and YPLL (median = 82%) were among working-age (20-64 years) adults. Routine monitoring of alcohol-attributable health outcomes, including deaths and YPLL, in states could support the planning and implementation of evidence-based prevention strategies recommended by the Community Preventive Services Task Force to reduce excessive drinking and related harms. Such strategies include increasing the price of alcohol, limiting alcohol outlet density, and holding alcohol retailers liable for harms related to the sale of alcoholic beverages to minors and intoxicated patrons (dram shop liability).

Workers' compensation injury claims of aviation industry worker injuries in Alaska, 2014-2015.

Aviation operations in Alaska often occur in remote locations and during inclement weather. Limited infrastructure and staff in some locations often requires aviation workers to perform tasks outside of their specific job descriptions. Researchers identified workers' compensation claims as a valuable data source to characterise nonfatal injuries among Alaskan aviation workers. Keyword searches of injury claim narrative fields and industry codes were used to identify potentially aviation-related workers' compensation claims during 2014-2015. These claims were manually reviewed to verify whether aviation related and manually coded according to the US Bureau of Labour Statistics' Occupational Injury and Illness Classification System. There were 875 aviation-related injury claims accepted during 2014-2015. Ramp/baggage/cargo agents incurred the most injuries (35%), followed by mechanics/maintenance workers (15%). Among all workers, Overexertion and Bodily Reaction (40%) was most often cited as the injury event, followed by Contact with Objects and Equipment (28%), and Falls, Slips, Trips (22%). Sprains, strains, tears were the most frequent nature of injury (55%). Cargo/freight/luggage was the most frequent source of injury (24%). The 3 most frequently identified injury event types were responsible for over 90% of all injuries, which indicates that preventive interventions should be directed towards tasks rather than occupational groups.

Using Workers' Compensation Claims Data to Describe Nonfatal Injuries among Workers in Alaska.

BACKGROUND: To gain a better understanding of nonfatal injuries in Alaska, underutilized data sources such as workers' compensation claims must be analyzed. The purpose of the current study was to utilize workers' compensation claims data to estimate the risk of nonfatal, work-related injuries among occupations in Alaska, characterize injury patterns, and prioritize future research. METHODS: A dataset with information on all submitted claims during 2014-2015 was provided for analysis. Claims were manually reviewed and coded. For inclusion in this study, claims had to represent incidents that resulted in a nonfatal acute traumatic injury, occurred in Alaska during 2014-2015, and were approved for compensation. RESULTS: Construction workers had the highest number of injuries (2,220), but a rate lower than the overall rate (34 per 1,000 construction workers, compared to 40 per 1,000 workers overall). Fire fighters had the highest rate of injuries on the job, with 162 injuries per 1,000 workers, followed by law enforcement officers with 121 injuries per 1,000 workers. The most common types of injuries across all occupations were sprains/strains/tears, contusions, and lacerations. CONCLUSION: The successful use of Alaska workers' compensation data demonstrates that the information provided in the claims dataset is meaningful for epidemiologic research. The predominance of sprains, strains, and tears among all occupations in Alaska indicates that ergonomic interventions to prevent overexertion are needed. These findings will be used to promote and guide future injury prevention research and interventions.

Factors associated with crewmember survival of commercial fishing vessel sinkings in Alaska.

Occupational fatality surveillance has identified that fishing vessel disasters, such as sinkings and capsizings, continue to contribute to the most deaths among crewmembers in the US fishing industry. When a fishing vessel sinks at sea, crewmembers are at risk of immersion in water and subsequent drowning. This study examined survival factors for crewmembers following cold water immersion after the sinking of decked commercial fishing vessels in Alaskan waters during 2000-2014. Two immersion scenarios were considered separately: immersion for any length of time, and long-term immersion defined as immersion lasting over 30 minutes. Logistic regression was used to predict the odds of crewmember survival. Of the 617 crewmembers onboard 187 fishing vessels that sank in Alaska during 2000-2014, 557 (90.3%) survived and 60 died. For crewmembers immersed for any length of time, the significant adjusted predictors of survival were: entering a life-raft, sinking within three miles of shore, the sinking not being weather-related, and working as a deckhand. For crewmembers immersed for over 30 minutes, the significant adjusted predictors of survival were: wearing an immersion suit, entering a life-raft, working as a deckhand, and the sinking not being weather-related. The results of this analysis demonstrate that in situations where cold water immersion becomes inevitable, having access to well-maintained, serviceable lifesaving equipment and the knowledge and skills to use it properly are critical.

Cdc42 in actin dynamics: An ordered pathway governed by complex equilibria and directional effector handover.

The small GTPase, Cdc42, is a key regulator of actin dynamics, functioning to connect multiple signals to actin polymerization through effector proteins of the Wiskott-Aldrich syndrome protein (WASP) and Transducer of Cdc42-dependent actin assembly (TOCA) families. WASP family members serve to couple Cdc42 with the actin nucleator, the Arp2/3 complex, via direct interactions. The regulation of these proteins in the context of actin dynamics has been extensively studied. Studies on the TOCA family, however, are more limited and relatively little is known about their roles and regulation. In this commentary we highlight new structural and biophysical insight into the involvement of TOCA proteins in the pathway of Cdc42-dependent actin dynamics. We discuss the biological implications of the low affinity interactions between the TOCA family and Cdc42, as well as probing the sequential binding of TOCA1 and the WASP homolog, N-WASP, to Cdc42. We place our current research in the context of the wealth of biophysical, structural and functional data from earlier studies pertaining to the Cdc42/N-WASP/Arp2/3 pathway of actin polymerization. Finally, we describe the molecular basis for a sequential G protein-effector handover from TOCA1 to N-WASP.

(1)H, (13)C and (15)N resonance assignments of the Cdc42-binding domain of TOCA1.

TOCA1 is a downstream effector protein of the small GTPase, Cdc42. It is a multi-domain protein that includes a membrane binding F-BAR domain, a homology region 1 (HR1) domain, which binds selectively to active Cdc42 and an SH3 domain. TOCA1 is involved in the regulation of actin dynamics in processes such as endocytosis, filopodia formation, neurite elongation, cell motility and invasion. Structural insight into the interaction between TOCA1 and Cdc42 will contribute to our understanding of the role of TOCA1 in actin dynamics. The (1)H, (15)N and (13)C NMR backbone and sidechain resonance assignment of the HR1 domain (12 kDa) presented here provides the foundation for structural studies of the domain and its interactions.